Synthesis of Lipid Based Polyols from 1-butene Metathesized Palm Oil for Use in Polyurethane Foam Applications

Transcription

1 Synthesis of Lipid Based Polyols from 1-butene Metathesized Palm Oil for Use in Polyurethane Foam Applications A Thesis Submitted to the Committee on Graduate Studies in Partial Fulfillment of the Requirements for the Doctor of Philosophy in the Faculty of Arts and Science TRENT UNIVERSITY Peterborough, Ontario, Canada Copyright by Prasanth Kumar Sasidharan Pillai 2015 Materials Science PhD. Graduate Program January 2016

2 Abstract Synthesis of Lipid Based Polyols from 1-Butene Metathesized Palm Oil for Use in Polyurethane Foam Applications Prasanth Kumar Sasidharan Pillai This thesis explores the use of 1-butene cross metathesized palm oil (PMTAG) as a feedstock for preparation of polyols which can be used to prepare rigid and flexible polyurethane foams. PMTAG is advantageous over its precursor feedstock, palm oil, for synthesizing polyols, especially for the preparation of rigid foams, because of the reduction of dangling chain effects associated with the omega unsaturated fatty acids. 1-butene cross metathesis results in shortening of the unsaturated fatty acid moieties, with approximately half of the unsaturated fatty acids assuming terminal double bonds. It was shown that the associated terminal OH groups introduced through epoxidation and hydroxylation result in rigid foams with a compressive strength approximately 2.5 times higher than that of rigid foams from palm and soybean oil polyols. Up to 1.5 times improvement in the compressive strength value of the rigid foams from the PMTAG polyol was further obtained following dry and/or solvent assisted fractionation of PMTAG in order to reduce the dangling chain effects associated with the saturated components of the PMTAG. Flexible foams with excellent recovery was achieved from the polyols of PMTAG and the high olein fraction of PMTAG indicating that these bio-derived polyurethane foams may be suitable for flexible foam applications. PMTAG polyols with controlled OH values prepared via an optimized green solvent free synthetic strategy provided flexible foams with lower compressive strength and ii

3 higher recovery; i.e., better flexible foam potential compared to the PMTAG derived foams with non-controlled OH values. Overall, this study has revealed that the dangling chain issues of vegetable oils can be addressed in part using appropriate chemical and physical modification techniques such as cross metathesis and fractionation, respectively. In fact, the rigidity and the compressive strength of the polyurethane foams were in very close agreement with the percentage of terminal hydroxyl and OH value of the polyol. The results obtained from the study can be used to convert PMTAG like materials into industrially valuable materials. Keywords Cross Metathesis; Metathesized Triacylglycerol (MTAG); Fractionation; Polyols; Hexol; Tetrol; Diol; Olein; Stearin; Glycerol Composition; Polyurethane Foams; Compressive Strength; Recovery. iii

4 Acknowledgements Its extreme pleasure to thank all the good hearted people who showered immense support and help in achieving this milestone. I would never be able to finish this Ph.D without the kind contributions from many of the wonderful people. In this pleasant occasion I would like to thank all these wonderful people from my heart. I would like to express my sincere thanks and respect to my supervisor, Prof. Suresh S. Narine for giving me this wonderful opportunity. At this time I thank him for his magnificent guidance and immense support throughout the program. He is a brilliant mentor as well as a good friend who cares a lot about the welfare of the people who depended on him. Without the priceless learning and incalculable experience obtained from him, I would not be able to finish this work. I would like to thank Dr. Laziz Bouzidi and Dr. Shaojun Li for their kind advices and valuable suggestions during my Ph.D. Also I take this opportunity to thank my supervisory committee members Dr. Andrew Vreugdenhil and Dr. Ghaus Rizvi for their kind advices and motivations. I would like to thank Professor Sabu Thomas for their immense and generous help showered one me on all my difficult times. I am also Thankful to Dr. Laly A. Pothen and Abraham Mathew for their immense support and motivation all the time. I have a million thanks for Ms. Athira Mohanan for her incredible and selfless support throughout the Ph.D. Without her unconditional support and valuable advices, I would not be able to finish my Ph.D. I am thanking all my colleagues Ms. Latchmi Regunanan, Ms. Shegufa Merchant, Mr. Michael Floros, Mr. Avinaash Persaud and Dr. Jesmy Jose for their kind help and valuable iv

5 suggestions throughout my Ph.D. Also I am grateful to our Lab managers and technicians Ali Mahdevari, Carolyn Payne, John Breukelar, Peter Andreas for their valuable supervision and support during this period. I would like to thank Rekha Singh, the administrative secretary of our group for her kind support on all difficult times during my Ph.D. I would like to thank the Grain Farmers of Ontario, Elevance Renewable Sciences, Trent University, the GPA-EDC, Ontario Ministry of Agriculture, Food and Rural Affairs, Industry Canada and NSERC for their financial support I thank all my friends for their valuable suggestions throughout my life. A special thanks to Mr. Tino Justin, Hassan Damji, Mohammed Jawad Nathoo and Mike Harrison Charles, who were always there with me on all my difficulties. I am also grateful to Dr. Swaroop Sasidharan Pillai, Dr. Dinesh T. Sreedharan for their precious support. Finally my appreciation goes to my family for their selfless support. Exclusively, I am always grateful to my parents, Sasidharan Pillai and Prasanna Kumari. I would like to thank my sister Sree Lekshmi. P and brother in law Sarath S. Kurup for their unconditional support and taking care my parents Sasidharan Pillai and Prasanna Kumari while I am miles away from home. Also I am so thankful to my uncle B. Sivan Pillai for his support and advices throughout my life. v

6 Table of Contents Abstract... ii Keywords... iii Acknowledgements... iv Table of Contents... vi List of Figures... xii List of Schemes... xvi List of Tables... xix List of Abbreviations... xxiii 1 Introduction Motivation and Objectives Background Polyurethanes Polyurethane foams Polyols Petroleum Polyols Vegetable Oil Based Polyols Factors Determining the Properties of PU Foams Effect of Polyol Structure Effect of Isocyanate Effect of Catalyst Effect of Blowing Agent Effect of Surfactant Problems of Vegetable oil Derived PU Foams vi

7 1.5 Rectification of Dangling Chain Issue Olefin Metathesis Fractionation by Crystallization Hypotheses Thesis Outline References Butene Metathesized Palm Oil & Polyol Derivatives: Structure, Chemical Composition and Physical Properties Introduction Materials and Methods Materials Chemistry characterization techniques Physical characterization techniques Results and Discussion Chemical Characterization of PMTAG Compositional Analysis of PMTAG Physical Properties of PMTAG Synthesis of PMTAG Polyol Compositional analysis of PMTAG Polyol Composition of PMTAG Polyol Physical Properties of PMTAG Polyol Conclusions References vii

8 3 Water-Blown Bio-Based Rigid and Flexible Polyurethane Foams from 1-Butene Metathesized Palm oil Polyol Introduction Materials and Methods Materials Polymerization Method Chemistry and Physical characterization techniques Preparation of PU rigid and flexible foams Results and discussion FTIR Characterization of Foams SEM analysis of PMTAG Polyol Foams Thermal Stability of Foams DSC of Rigid and Flexible Foams Compressive Strength of PMTAG Polyol Foams Recovery of Flexible Foams Conclusions References Fractionation Strategies for Improving Functional Properties of Polyols and derived Polyurethane Foams from 1-butene Metathesized Palm Oil Introduction Materials and Methods Materials Chemistry Characterization Techniques Titrimetric Methods (OH value, Acid value, Iodine value) viii

9 4.3.2 Proton Nuclear Magnetic Resonance Spectroscopy ( 1 HNMR) Fourier Transform Infrared Spectroscopy (FTIR) Physical Characterization Techniques Thermogravimetric Analysis (TGA) Differential Scanning Calorimetry (DSC) Rheology Scanning Electron Microscopy (SEM) Compressive Strength Fractionation of PMTAG by dry and solvent mediated crystallization Dry crystallization experiments Solvent Mediated Crystallization Experiment Synthesis of the Polyols Epoxidation Hydroxylation Polymerization Method Results and Discussion Results of the fractionation of PMTAG H-NMR Characterization of the PMTAG fractions Characterization of the polyols synthesized from LF- and SF-PMTAG Crystallization and Melting Behavior of LF- and SF- Polyols Flow Behavior and Viscosity of LF- and SF-PMTAG Polyols ix

10 4.9 Polyurethane Rigid and Flexible Foams FTIR of LF-PMTAG Polyol Foams SEM Analysis of LF-Polyol Foams Thermal degradation Properties of LF-Polyol Foams Thermal transition Properties of LF-Polyol Foams Compressive Strength of LF-Polyol Foams Conclusions References Solvent Free Synthesis of Polyols From 1- Butene Metathesized Palm Oil for Use in Polyurethane foams Introduction Materials and Methods Materials Chemistry Characterization Physical Characterization Techniques Synthesis Methods Results and Discussion Solvent Free Synthesis of Polyol from PMTAG Chemical Characterization and Compositional Analysis of PMTAG Green Polyols Physical Properties of PMTAG Green Polyols Polyurethane Foams x

11 5.4 Conclusions References Conclusion General Conclusion Rigid foams from PMTAG Flexible foams from PMTAG Foams from fractionated PMTAG Green Polyols and Foams Summary Implications of this study Future Prospects Appendix A1 Butene Cross metathesized Palm oil and Polyol Derivatives: Structure and Physical properties A2 A3 Fractionation Strategies for Improving Functional Properties of Polyols and derived Polyurethane Foams from 1-butene Metathesized Palm Oil Solvent Free Synthesis of Polyols from 1-Butene Metathesized Palm Oil for Use of Polyurethane Foams xi

12 List of Figures Figure H-NMR of PMTAG. (a) Chemical shift range between δ 2.5 and 0.7 ppm, (b) Chemical shift range between δ 6.0 and 4.0 ppm Figure 2.2. HPLC of PMTAG (solid line) superimposed with the HPLC of DDD, DDS and DSS. The standard TAGs are indicated at the side of their HPLC trace (dashed lines) Figure 2.3: TGA and DTG profiles of the PMTAG Figure 2.4: (a) Crystallization thermograms of PMTAG obtained (b) corresponding heating profiles (both at 5 C/min) Figure 2.5: Shear rate versus shear stress of the PMTAG Figure 2.6: Viscosity versus temperature of PMTAG. Dotted lines are fit to the generalized van Velzen equation (eq.2). The lower panel represents the residuals in % (RD%) versus temperature Figure H-NMR spectrum of epoxy PMTAG Figure H-NMR of (a) PMTAG Polyol H1and (b) PMTAG Polyol H2 and H Figure 2.9. HPLC of PMTAG Polyol Figure 2.10: TGA and DTG profiles of PMTAG Polyol Figure 2.11: (a) Crystallization of PMTAG polyol (b) heating profile of PMTAG polyol.. 84 Figure 2.12: Shear rate versus shear stress of PMTAG Polyol Figure 2.13: Viscosity versus temperature measured while cooling PMTAG Polyol at ( ) 1 C/min. Dotted lines represent the calculated viscosity using the generalized van Velzen equation (Eq.2.2). Lower panel represent the residuals in % (RD%) versus temperature. The cut-off is indicated with a vertical dashed line xii

13 Figure 3.1: Pictures of (a) Rigid PMTAG Polyol Foam, and (b) Flexible PMTAG Polyol Foam Figure 3.2. Typical FTIR spectra of the PMTAG Polyol foams. (1) PMTAG Polyol Rigid Foam and (2) PMTAG Polyol Flexible Foam Figure 3.3. Typical SEM micrographs of (a) Rigid PMTAG Polyol foams and (b) Flexible PMTAG Polyol Foam Figure 3.4: TGA and DTG profiles of (a) PMTAG rigid foam and (b) PMTAG flexible foam Figure 3.5. Typical DSC curves of (a) Rigid PMTAG Polyol Foam and (b) Flexible PMTAG Polyol Foam Figure 3.6. (a) Compressive strength versus strain curves of PMTAG Polyol foams (a) rigid foam (b) flexible foams Figure 3.7. Density (kg/m 3 ) versus compressive strength (MPa) of PMTAG Polyol foams at 6% and 10% deformations (a) rigid foam (b) flexible foam Figure 3.8. (a) Recovery of PMTAG Flexible Foam as a function of time (min); (b) Recovery of PMTAG Flexible Foam after 48 h as a function of density Figure 4.1. Crystallization thermograms of PMTAG obtained at 0.1 C/min, 1 C/min and 5 C/min Figure 4.2. Typical DSC thermograms of the liquid (LF) and solid fractions (SF) of PMTAG. (a) cooling and (b) heating (both at 5 C/min) Figure 4.3. DTG of LF- and SF-Polyols xiii

14 Figure 4.4. DSC thermograms of LF- and SF-Polyols obtained from the liquid fractions and solid fractions of PMTAG during (a) Cooling (5.0 C/min), and (b) subsequent heating (5 C/min) Figure 4.5. (a) Shear rate- shear stress of LF-Polyol), (b) viscosity versus temperature of LFand SF-Polyols. Solid lines in (a) are fits to the Herschel-Bulkley model (Eq. 4.1) Figure 4.6. Typical FTIR spectra of the rigid (RF) and flexible foams (FF) prepared from LF- Polyol Figure 4.7. SEM images of rigid and flexible LF-Polyol foams: (a) rigid foam, (b) flexibe foam Figure 4.8. (a) DTG of rigid (RF) and flexible (FF) LF-Polyol foams Figure 4.9. DSC thermogram of rigid (RF) and flexible (FF) LF-Polyol foams Figure Compressive strength versus strain curves of (a) Rigid LF-Polyol foam of density 163 kg/m 3 (RF) and (b) Flexible LF-Polyol Foam of density 161 kg/m 3 (FF) Figure Recovery of LF-Polyol Flexible Foam (FF) as a function of time (min) Figure 5.1. DTG profiles of B3- and B4-Green Polyols Figure 5.2. DSC thermograms of B3-, and B4-Green Polyols obtained during (a) Cooling, and (b) subsequent heating (5 C/min) Figure 5.3. Shear rate- shear stress of PMTAG Green Polyols. (a) B3-Green Polyol (b) B4- Green Polyol, respectively Figure 5.4. Viscosity versus temperature curves obtained during cooling (1 C/min) of B3- Green Polyol (empty circles) and B4-Green Polyol (empty triangles). Dashed lines are guides for the eye xiv

15 Figure 5.5: Pictures of rigid and flexible foams from B3-and B4-Green PMTAG Polyols. (a) B3-Green Polyol rigid foam of density 145 kgm -3 (B3-RF145), (b) B3-Green Polyol flexible foam of density 162 kgm -3 (B3-FF162), (c) B4-Green Polyol rigid foam of density 166 kgm - 3 (B4-RF166).and (d) B4-Green Polyol flexible foam of density 156 kgm -3 (B4-FF156) Figure 5.6. Typical FTIR spectra of rigid (RF) and flexible (FF) B4-Green Polyol foam. 181 Figure 5.7. SEM micrographs of (a) B4-Green Polyol rigid foam and (b) B4-Green Polyol flexible foam Figure 5.8. DTG curves of B4-Green Polyol rigid foam (B4-RF) and B4-Green Polyol Flexible Foam (B4-FF) Figure 5.9. DSC heating thermogram (2 nd cycle) of the B4-Green Polyol rigid (B4-RF) and flexible foams (B4-FF): arrow 1 indicatest g low, arrow 2 indicates T g int and arrow 3 indicatest g high Figure Compressive strength versus strain curves of (a) Rigid foams: B3-RF145 (B3- Green Polyol rigid foam of density 145 kgm -3 ), B4-RF166 (B4-Green Polyol rigid foam of density 166 kgm -3 ) (b) Flexible foams. B3-FF162 (B3-Green Polyol flexible foam of density 162 kgm -3 ), B4-FF156 (B4-Green Polyol flexible foam of density 156 kgm -3 ) Figure 5.11: Recovery (%) in thickness of B4-FF156 (B4-Green Polyol flexible foam of density 156 kgm -3 ) versus time Figure A 1: 1 H-NMR of Epoxidation of PMTAG in Ethyl Acetate. Terminal double bond left : >60% Figure A 2: 1 H-NMR of Epoxidation of without solvent. No double bond detected. Formic ester polyol formed. Terminal double bond left : >60% xv

16 Figure A 3: 1 H-NMR of Epoxidation of with reduced ratio of H2O2 and HCOOH. Terminal double bond >40% and Internal double bond >5% Figure A 4. HPLC of PMTAG Polyol Fractions (F1-F8) Figure A 5: Crystallization thermograms of (a) LF(D)-PMTAG, (b)sf(d)-pmtag obtained at 5 C/min and heating profiles of (c) LF(D)-PMTAG, (d) SF(D)-PMTAG at 5 C/min Figure A 6: Crystallization thermograms of (a) LF(S)-PMTAG, (b)sf(s)-pmtag obtained at 5 C/min and heating profiles of (c) LF(S)-PMTAG, (d) SF(S)-PMTAG at 5 C/min Figure A7. 1 H-NMR spectra of SF-PMTAG Figure A 8. 1 H-NMR spectra of LF-PMTAG Figure A 9. 1 H-NMR spectra of LF-Polyol Figure A H-NMR spectra of SF-Polyol Figure A 11: 1HNMR of Selected Polyols Figure A 12. GPC chromatogram of B3-Green Polyol (B3), B4-Green Polyol (B4) and standard PMTAG polyol (S) List of Schemes Scheme 1.1: Reaction of isocyanate and alcohol to form urethane linkage... 4 Scheme 1.2: Possible reactions during polyurethane foam preparation... 5 Scheme 1.3: General formula of polyalkylene oxide (polyether) polyol... 7 Scheme 1.4: General formula of polyester polyol... 7 Scheme 1.5: General structure of a triacylglycerol (TAG); R1, R2 and R3 are fatty acids, and may or may not be the same... 8 xvi

17 Scheme 1.6: Ozonolysis of vegetable oil TAGs to produce polyols[47] Scheme 1.7: Hydroformylation of vegetable oil TAGs to produce polyols Scheme 1.8: Transesterification of vegetable oil TAGs using glycerol to produce polyols. 13 Scheme 1.9. Epoxidation reaction of TAG to yield polyol Scheme Representation of olefin metathesis reaction [100]. Forward reaction (from left to right) shows the self -metathesis reaction; reverse reaction (from right to left) gives the cross metathesis reaction Scheme 2.1. Representation of olefin metathesis reaction Scheme 2.2. Metathesis reaction of triolein with 1-butene. n=0, the fatty acid is 9-denenoic acid (D), n= 2, the fatty acid is 9-dodecenoic acid (Dd), and n= 8, the fatty acid is oleic acid (O) Scheme 2.3. Possible TAG structures composing PMTAG. n=0, 2, 8; m= 11 to Scheme 2.4. Synthesis of PMTAG Polyol (n=0, 2, 8; m=11 to 20) Scheme 2.5. Diol structures produced from oleic acid, 9-dodecenoic acid and 9-decenoic acid present in the PMTAG as a result of epoxidation followed by hydroxylation Scheme 2.6. General structures present in PMTAG Polyol (n= 0, 2, 8; m=11 to 20) Scheme 3.1. Cross linked polyurethane foam from MDI and PMTAG Polyols. Hexol is used as a model polyol structure Scheme 4.1. Synthesis route of polyols from the liquid and solid fraction of PMTAG (n=0, 2, 8; m=11 to 20) Scheme 4.2. Possible TAG structures in LF-and SF-PMTAG. n=0, 2, 8; m= 11 to Scheme 4.3. Possible structures of LF- and SF-Polyols (n= 0, 2, 8; m=11 to 20) Scheme 5.1. Solvent-free synthesis of polyols from PMTAG. n= 0, 2, 8; m= 11 to Scheme 5.2. General structures in PMTAG Green Polyol (n= 0, 2, 8; m= 11 to 20) xvii

18 Scheme A 1. Possible structure of the formic ester polyol Scheme A 2. Structures of PMTAG Polyol determined by MS and 1 H-NMR Scheme A3. Fatty acid (FA1, FA2 and FA3) structures from the B4-Polyol xviii

19 List of Tables Table 1.1: Some common fatty acids in vegetable oils [8]. The first number in brackets gives is the number of carbon atoms in the fatty acid chain and the second number indicates the number of double bonds Table 1.2: Fatty Acid Composition (%) of some typical vegetable oils (Modified from [10, 58, 59]) Table 2.1. TAG profile of palm oil and corresponding modified TAG in PMTAG Table 2.2. GC results of methylated PMTAG Table 2.3. Relative amounts of saturated and unsaturated structures in PMTAG as determined by 1 H-NMR Table 2.4. HPLC analysis data of PMTAG Table 2.5. Optimization data for the synthesis of PMTAG Polyol a Table 2.6. Characterization of PMTAG Polyol fractions Table 2.7. HPLC retention time (RT, min) and relative area (A%) of column chromatography fraction of PMTAG polyol (F1-F8) obtained from the analysis of the HPLC of PMTAG Polyol Table 2.8. Thermal data of the PMTAG and PMTAG Polyol obtained on cooling and heating (5 C/min). T on, T off, and p T, p= 1-6: onset, offset, and peak temperatures,, H CM : Enthalpy, C: crystallization and M: melting Table 3.1. Formulation Recipe for Rigid and Flexible PMTAG Polyol Foam Table 3.2. Composition and properties of PMTAG Polyol and diphenylmethane diisocyanate (MDI) xix

20 Table 3.3. Reactivity profile for the processing of PMTAG Polyol rigid and flexible foams Table 3.4. Compressive strength of vegetable polyol based rigid foams from the literature[7, 43] Table 4.1. Fractionation data of PMTAG. a T C : Crystallization temperature; bt C : isothermal crystallization time Table 4.2. Formulation Recipes for Rigid and Flexible Foams Table 4.3. Fatty acid profile of SF-PMTAG and LF-PMTAG calculated based on the relative area under the characteristic 1 H-NMR peaks assuming TAG structures only. The PMTAG data are provided for comparison purposes. TDB: Terminal double bonds; IDB: Internal double bonds; FA: Fatty acid; SFA: Saturated fatty acid Table 4.4. Compressive strength of LF-PMTAG Polyol Foams at different strain (%): Rigid LF-Polyol Foam (RF), Flexible LF-Polyol Foam (FF); Rigid PMTAG Polyol Foam (RF- PMTAG Polyol); and Flexible PMTAG Polyol Foam (FF-PMTAG Polyol) Table 5.1. Epoxidation reaction temperature and time data for the synthesis of green polyols. Epx T ini Epx : Initial temperature of the epoxidation reaction; T max : highest temperature reached during the epoxidation reaction; Epx T R : reaction temperature for epoxidation; Epx t R : reaction time 166 Table 5.2. Formulation Recipes for Rigid and Flexible Foams. Amounts are based on 100 parts by weight of total polyol Table 5.3. Amount of remaining terminal double bonds (RTDB) 1, number of formic acid units per TAG polyol and terminal OH groups as estimated by 1 H-NMR. Iodine value, Acid value and OH number of PMTAG Green Polyols xx

21 Table 5.4. Compressive strength of rigid foams: B4-RF166 (B4-Green Polyol rigid foam of density 166 kgm -3 ) versus RF-165 (PMTAG Polyol rigid foam of density 165 kgm -3 )at 6% and 10 % deformation. Flexible Foams: B3-FF162 (B3-Green Polyol flexible foam of density 162 kgm -3 ), B4-FF156 (B4-Green Polyol flexible foam of density 156 kgm -3 ) and FF-156 (PMTAG Polyol flexible foam of density 156 kgm -3 ) at 10% and 25% deformation Table A 1. Table showing the characteristic chemical shift values of PMTAG Table A 2. Thermal data of the PMTAG obtained on cooling and heating (at 0.1, 1.0, 5 C/min). T on, Toff and p T, p= 1-6: Onset, offset, and peak temperatures, H CM, : Enthalpy, C: crystallization and M: melting Table A 3. Fractionation of PMTAG by crystallization. T On : onset of crystallization Table A 4. Thermal data of SF- and LF-PMTAG. T on, T off, T1 3 : onset, offset and peak temperatures ( C),, HO, and H (J/g): Enthalpy of the stearin and olein portions, and H S total enthalpy, respectively Table A 5. 1 H-NMR chemical shifts of SF-PMTAG and LF- PMTAG Table A 6: Chemical shifts (δ) and their integration values from 1 HNMR Table A 7. Temperature of degradation at 1, 5 and 10% weight loss ( 1% d d d T, T, 5% T, 10% respectively), DTG peak temperatures ( T D ), and extrapolated onset ( T on ) and offset ( off T ) temperatures of degradation of LF- and SF- Polyols xxi

22 Table A 8. Thermal data of LF- and SF-Polyols obtained on cooling and heating (both at 5 C/min). Onset ( T on ), offset ( T ), and peak temperatures ( T off 1 3 ), Enthalpy of crystallization ( HC ), and Enthalpy of melting ( H M ). a Shoulder peak d d d Table A 9. Temperature of degradation at 1, 5 and 10% weight loss ( T 1%, T 5%, T 10%, respectively), DTG peak temperatures ( T D ), and extrapolated onset ( T on ) and offset ( T off ) temperatures of degradation of LF(D)-Polyol Foams Table A 10: Properties of diphenylmethane diisocyanate (MDI) Table A H-NMR chemical shifts, δ, of B1-, B2-, B3- and B4-epoxy PMTAG Table A H-NMR chemical shifts, δ, of B1-, B2-, B3- and B4-PMTAG Green Polyols Table A 13. Area% of peaks P1 and P2 from GPC Table A 14. Column chromatography, HPLC and 1 H NMR data of the fractions of B4-Polyol. EA: Hx: ratio of ethyl acetate and hexanes, the solvents used for column chromatography. RT: HPLC Retention time (min); FA1: Fatty acids with terminal double bond (9-decenoic acid), FA2: Fatty acid with internal double bond (9-dodecenoic acid); FA3: Fatty acid with internal double bond (oleic acid). The structure FA1, FA2 and FA3 are presented in Scheme A Table A15. Thermal data of Green PMTAG Polyols obtained on cooling and heating (both at 5 C/min). Onset ( T on ), offset ( T off ), and peak temperatures ( T 1 3 ), enthalpy of crystallization ( HC ), and enthalpy of melting ( H M ). a Shoulder peak xxii

23 List of Abbreviations Acronym Name B1-Green Polyol Polyol from PMTAG from Batch 1-solvent free method B2-Green Polyol Polyol from PMTAG from Batch 2-solvent free method B3-Green Polyol Polyol from PMTAG from Batch 3-solvent free method B4-Green Polyol Polyol from PMTAG from Batch 4-solvent free method B3-FF162 B3-Green Polyol Flexible Foam: Density 162 kgm -3 B4-FF156 B4-Green Polyol Flexible Foam: Density 156 kgm -3 B3-RF145 B3-Green Polyol Rigid Foam: Density 145 kgm -3 B4-RF166 B4-Green Polyol Flexible Foam: Density 166 kgm -3 CFC Chlorofluorocarbon DBTDL Dibutyltindilaurate DDD 1,2,3-triyl tris(dec-9-enoate) DDS 3-(dec-9-enoyloxy) propane-1, 2-diyl distearate DMBNA N,N-dimethylbenzylamine DMEA N,N-Dimethylethanolamine DSS 3-(stearoyloxy) propane-1, 2-diyl bis(dec-9-enoate) DDO 3-(dec-9-enoyloxy) propane-1, 2-diyl oleate DDP 3-(dec-9-enoyloxy) propane-1, 2-diyl palmitate DDS 3-(dec-9-enoyloxy) propane-1, 2-diyl distearate DSS 3-(stearoyloxy) propane-1, 2-diyl bis(dec-9-enoate) DDdDd 3-(dodec-9-enoyloxy) propane-1, 2-diyl dec-9-enoate DOO 3-(oleoyloxy) propane-1, 2-diyl bis(dec-9-enoate) DLO 1-dec-9-oyl-2-linoleoyl-3-oleoyl-sn-glycerol DOP 1-decenoyl-2-oleoyl-3-palmitoyl-sn-glycerol DdDdDd 1,2,3-triyl tris(dodec-9-enoate DdDdS 3-(dodec-9-enoyloxy) propane-1, 2-diyl distearate DdDL 1-dodecenoyl-2-decenoyl-3-linoleoyl-sn-glycerol DdDdL 3-(dodec-9-enoyloxy) propane-1, 2-diyl linoleate DdDdO 3-(dodec-9-enoyloxy) propane-1, 2-diyl oleate DdDdP 3-(dodec-9-enoyloxy) propane-1, 2-diyl palmitate DdDP 1-dodecenoyl-2-decenoyl-9-palmitoyl-sn-glycerol DdLO 1-dodecnoyl-2-linoleoyl-3-oleoyl-sn-glycerol DdOP 1-dodecenoyl-2-oleoyl-3-palmitoyl-sn-glycerol Epoxy B1-PMTAG Epoxy of PMTAG from Batch 1-solvent free method Epoxy B2-PMTAG Epoxy of PMTAG from Batch 2 -solvent free method Epoxy B3-PMTAG Epoxy of PMTAG from Batch 3-solvent free method Epoxy B4-PMTAG Epoxy of PMTAG from Batch 4-solvent free method FF Flexible Foam HDI Hexamethylene diisocyanate HFC Hydrofluorocarbon HCFC Hydrochlorofluorocarbon IPDI Isophorone diisocyanate LF Liquid Fraction xxiii

24 IV LF-Polyol LF-PMTAG MAG MDI MTAG MLP MMM MMP OOO OOL OOP OLO PMTAG PU PMTAG Polyol PMTAG-FF PMTAG-RF PLL PLP POL POO POP POS PPM PPO PPP PPS TAG RF SF SF-PMTAG SF-Polyol SFA SOO SOS TAG TDI UFA Iodine Value Liquid Fraction from PMTAG Polyol Liquid Fraction of PMTAG Monoacylglycerols Diphenylmethane diisocyanate Metathesized Triacylglycerol 1-myristoyl-2-linoleoyl-3-palmitoyl-sn-glycerol trimyristoylglycerol 1,2-dimyristoyl-3-palmitoyl-sn-glycerol Triolein 1,2-dioleoyl-3-linoleyol-sn- glycerol 1,2-dioleoyl-3-palmitoyl-sn- glycerol 1,3-dioleoyl-2-linoleoyl-sn-glycerol MTAG of Palm Oil Polyurethane Polyol synthesized from PMTAG by solvent method Flexible Foam prepared from PMTAG Polyol Rigid Foam prepared from PMTAG Polyol 1,2-dilinoleyol-3-palmitoyl-sn- glycerol 1,3-palmitoyl-2-linoleoyl-sn-glycerol 1-palmitoyl-2-oleoyl-3-linoleoyl-sn-glycerol 1,2-dioleoyl-3-palmitoyl-sn- glycerol 1,3-dipalmitoyl-2-oleoyl-sn-glycerol 1-palmitoy-l,2-oleoyl,3-stearoyl-sn-glycerol 1,2-dipalmitoyl-3- myristoyl -sn-glycerol 1,2-dipalmitoyl-3- oleoyl -sn-glycerol tripalmitoylglycerol 1,2-dipalmitoyl-3-steroyl-sn-glycerol Triacylglycerol Rigid Foam Solid Fraction Solid Fraction of PMTAG Solid Fraction from PMTAG Polyol Saturated Fatty Acid 1,2-dioleoyl-3-stearoyl-sn- glycerol 1,3-distearoyl-2-oleoyl-sn-glycerol Triacylglycerol Toluene diisocyanate Unsaturated Fatty Acid xxiv

25 To My Parents & My Teacher, Dr. Laly A. Pothen xxv

26 1 Introduction 1.1 Motivation and Objectives Polyurethane (PU) foams are one of the most versatile polymeric materials with regards to both processing methods and mechanical properties [1, 2]. They are widely used because of their physical properties such as light weight, good insulation properties, excellent strength to weight ratio, and impressive sound absorbing properties [1, 2]. The PU foam market is very large and growing due to high demand across a wide range of industries such as automotive, building and construction, and packaging [3, 4]; the worth of the global polymer foams market was $82.6 billion in 2012 and is estimated to reach $131.1 billion by 2018 [5]. The specific polyurethane foams market value which was 46.8 billion in 2014 is expected to reach $72.2 billion by 2020 [6]. Traditionally, PU foams are prepared by the reaction of diisocyanates or polyisocyanates with petroleum-derived polyols [1, 7]. Growing concerns surrounding sustainability, biodegradability, control of carbon dioxide emission and other environmental problems are driving a strong demand for alternatives to petroleum as a feedstock for fuels and materials [8]. Vegetable oils are advantageous in this regard because of their availability in large quantities, renewability and relatively low cost [9-11]. Studies on the preparation of rigid and flexible PU foams from vegetable oils (VO) were already reported; for example PU foams from soybean oil [12-15], castor oil [16], safflower oil, corn oil, sunflower seed oil, linseed oil [17, 18], rapeseed oil [19-21] and cotton seed oil [22]. However, the dangling chains which remain in the PU foams from the saturated fatty acids as well as from the omega chains of the unsaturated fatty acid of VOs negatively 1

27 affect the rigidity of the foams [23]. The regions where dangling chains are present do not support stress when the sample is loaded. Furthermore, they act as plasticizers, resulting in reduction of polymer rigidity [24, 25]. This can be addressed by modifying vegetable oils using more appropriate methods such as olefin cross-metathesis, ozonolysis, fractionation etc., such that dangling chains are removed. Palm oil is one of the cheapest, most produced TAG oils, making it an ideal feedstock replacement at an industrial scale. It is primarily used in foods [26, 27] and is increasingly sought for the production of industrial materials. Palm oil is typically composed of 95% triacylglycerols (TAGs), 5% diacylglycerols (DAGs), and other minor components such as monoacylglycerols (MAGs) with a fatty acid profile ranging typically from C12 to C20 [28, 29]. It has a balanced saturation (~50/50 % of saturates / unsaturates) [30, 31]. Palmitic acid (P, C16:0) and oleic acid (O, C18:1) with ~43% and ~41%, respectively, are the main components of palm oil. Palm oil includes ~10% linoleic acid (Li, C18:2), and trace amounts of linolenic acid (Ln, C18:3) and palmitoleic acid (C16:1). Other representative saturated fatty acids, which are present in non-significant amounts (< 5 %), in palm oil are lauric acid (L, C12:0), myristic acid (M, C14:0), stearic acid (S, C18:0) and arachidic acid (A, C20:0). The TAG profile of palm oil shows a carbon distribution of C46 to C52 consisting of tri-unsaturated ( %), di-unsaturated ( %), mono unsaturated ( %) and saturated TAGs. Despite the high saturation, palm oil has been successfully transformed into a variety of industrial materials [32]. It is increasingly used to make value added products such as soaps and detergents [33], lubricants [34, 35], biodiesel [30, 36] and surfactant [37]. Palm oil and its derivatives are also actively investigated as a feedstock for the synthesis of 2

28 polyols to prepare polyurethanes [32, 38, 39]. However, its larger use in the production of polyurethanes is affected by its relatively higher levels of saturation (50% fatty acids) which limits the hydroxyl values of its polyols as compared to the polyols of highly unsaturated vegetable oil [40]. This restricts the applicability of palm oil-based polyols in polymer formulations, particularly in rigid polyurethane foams [40]. Cross metathesis [41] is a widely used chemical technique to convert the internal double bonds of unsaturated fatty acids into terminal double bonds, thereby removing the dangling chains associated with the unsaturated fatty acids. 1-butene metathesized palm oil, called PMTAG, is a by-product of the industrial biorefinery that produces 1-decene and 3,4-dodecene linear aliphatic olefins for the fine chemicals sector. Our industrial collaborator, Elevence Renewable Sciences (ERS, Bolingbrook, Ill., USA), owns the intellectual property right to convert palm oil into PMTAG [42]. ERS currently operates a biorefinery plant in Indonesia which processes 400 million lbs of palm oil, and plans to build other biorefinery processing plants in North America that will use cross-metathesis on native plant oils such as soybean oil and canola oil. This will increase the amount of these types of byproducts; i.e., metathesized vegetable oils. Conversion of these byproducts into value added products is, therefore, desirable in order to increase the profitability of the industry. The present study investigated whether PMTAG can be used to produce rigid and flexible PU foams. The objective of the study was not only to convert a byproduct into useful material, but also to contribute to the fundamental understanding necessary to address the dangling chain issues of vegetable oil derived PU foams. The potential for cross metathesis of palm oil followed by fractionation of saturated components to address the 3

29 dangling chain issues of palm oil was investigated. For this purpose, PMTAG was used to synthesize several polyols with variable hydroxyl value and terminal hydroxyls for the preparation of rigid and flexible polyurethane foams. The possibility to remove the saturated components of PMTAG using crystallization fractionation was also investigated and the fractionated PMTAG was used for the preparation of polyols and polyurethane foams. 1.2 Background Polyurethanes Polyurethanes are macromolecules containing urethane linkages (-NH-CO-O-) that are formed either based on the reaction of isocyanate (-NCO) groups and hydroxyl groups [1], or via non-isocyanate pathways, such as the reaction of cyclic carbonates with amines [43], self-polycondensation of hydroxyl-acyl azides or melt transurethane methods [44]. The most common method to form the backbone urethane group is the reaction of a polyol and an isocyanate with suitable cross-linking agents, chain extenders, blowing agents and other additives [45]. Scheme 1.1: Reaction of isocyanate and alcohol to form urethane linkage Scheme 1.1 shows the formation of a urethane linkage from the reaction of a hydroxyl group and an isocyanate. The appropriate selection of reactants enables the 4

30 formation of a wide range of polyurethane products such as polyurethane elastomers [46], sheets [47], adhesives [48], coatings [49] and foams [23] Polyurethane foams As discussed above, polyurethane foams are obtained by the reaction between polyols and diisocyanates or polyisocyanates in the presence of physical or chemical blowing agents [1, 7]. Polyurethane foam preparation involves two major simultaneous reactions: the cross linking reaction (see Scheme1.2a) and the blowing reaction (gas producing) (scheme 1.2b & 1.2c). The cross linking reaction leads to the formation of the urethane linkage [50, 51]. The subsequent reaction between isocyanate and water produces unstable carbamic acid which decomposes further into amine and carbon dioxide (see Scheme 1.2c). The carbon dioxide gas diffuses into the trapped air bubbles in the reaction mixture, causing the foam to rise. Scheme 1.2d shows the formation of a urea linkage by the reaction of excess of isocyanate with amine (see Scheme 1.2c).. Scheme 1.2: Possible reactions during polyurethane foam preparation The progress of the polyurethane foaming process can be monitored by the cream time, gel time and rise time. Cream time is defined as the time at which the polymerization mixture becomes creamy and brightened. Gel time is the time at which the increasing cross- 5

31 linking results in a gel-like or syrup-like polymer consistency. Rise time is the time period between the gel time and end of rise of the foams [1]. Furthermore, the physical properties of foams can be tailored to a large extent by varying the structure and composition of the reacting monomers, amount of catalyst and other additives (such as glycerin and water), as well as the reaction conditions used in the foam preparation [52]. PU foams may be classified as rigid or flexible according to the compressive strength value, cross link density, and OH value of the starting polyol [1]. Polyols having high molecular weight and low functionality yield flexible polyurethane foams [53] whilst polyols with low molecular weight and high functionality give rigid polyurethane foams [54] Polyols Polyols are a class of organic compounds with more than one hydroxyl functional groups. They can be used as monomers for making polyurethanes. The properties of the polyols such as hydroxyl value, molecular weight and functionality have important effects on the polyurethane properties [1, 7, 55]. The hydroxyl value of the polyol represents the reactive hydroxyl functionality in the molecule and is defined as the number of milligrams of potassium hydroxide (KOH) required to neutralize one gram of acetylated chemicals containing free hydroxyls [56] Petroleum Polyols Traditionally, polyurethane foams are prepared from petroleum derived polyols such as polyether and polyester polyols [1, 56]. Polyether polyols are widely used for the 6

32 preparation of polyurethane foams and elastomers [1, 7]. Polyether polyols are obtained by the polymerization of alkylene oxide initiated by different hydroxyl containing molecules such as ethylene glycol, propylene glycol or other polyols [7]. Scheme 1.3 represents the general structure of polyether polyols. The grafting of polymers on the polyether polyol backbone results in polymer polyols that are widely used for flexible foam applications. Polyester polyols are molecules with ester linkages used for the preparation of segmented polyurethane thermoplastics with good mechanical properties [7]. Polyesters are synthesized by the polycondensation reaction of a diacid, such as adipic or phthalic acid, with a diol, such as ethylene glycol or propylene glycol [7]. Scheme 1.4 presents general formula of a polyester polyol. Scheme 1.3: General formula of polyalkylene oxide (polyether) polyol Scheme 1.4: General formula of polyester polyol 7

33 1.2.5 Vegetable Oil Based Polyols Vegetable oil based polyols are synthesized by the modification of vegetable oil TAGs at their double bonds or ester linkages by the appropriate chemical reactions [2, 10, 57]. Vegetable oils consist of ~ 95 % triacylglycerols (TAG), which are the triesters of fatty acids and glycerol. Scheme 1.5: General structure of a triacylglycerol (TAG); R1, R2 and R3 are fatty acids, and may or may not be the same. Scheme 1.5 shows the general structure of a TAG. R1, R2 and R3 are aliphatic long chain fatty acids usually containing carbon atoms in their linear back bone. The fatty acid profiles of TAGs are not unique; they vary from vegetable oil to vegetable oil. The properties of vegetable oils, therefore, are highly dependent on their fatty acid composition. The major saturated and unsaturated fatty acids present in vegetable oils are listed on the Table 1.1, and the typical profiles of some of the more common vegetable oils are presented in Table

34 Table 1.1: Some common fatty acids in vegetable oils [8]. The first number in brackets gives is the number of carbon atoms in the fatty acid chain and the second number indicates the number of double bonds. (C16:0) (C16:1) (C18:0) (C18:1) (C18:2) (C18:3) (C18:1 OH) 9

35 Table 1.2: Fatty Acid Composition (%) of some typical vegetable oils (Modified from [10, 58, 59]). Fatty Acid Composition (% of total fatty acids) Seed Oil Palmitic acid Palmitoleic acid Stearic acid Oleic acid Linoleic acid Linolenic acid Sunflower Soybean Cottonseed Corn Olive Palm Rapeseed Linseed Sesame Cashew nut Canola Castor* * ricinoleic acid content = 87% Ozonolysis [2, 47, 65], hydroformylation [2, 59], epoxidation [2, 66] and transesterification [2, 67] are some of the key modification techniques that have been used for the insertion of hydroxyl groups at unsaturated sites in the TAGs. Furthermore, the selection of the synthetic method has a large influence on the type of polyol and their properties [68, 69]. For example, the hydroxyl value (OH value) of a given polyol - which 10

36 has huge impact on the physical properties of the resulting foam- varies with the different modification techniques adopted for the synthesis of polyol [70]. Ozonolysis [47] followed by hydrogenation gives polyols with terminal hydroxyl groups [68]. Scheme 1.6 shows the ozonolysis of TAGs to produce polyols. This method uses ozone to cleave and oxidize the double bonds in TAGs into the corresponding ozonide intermediates. The ozonides thus produced are further hydrogenated into polyols using Raney Nickel catalyst [68]. However the polyols prepared by this method contain only one hydroxyl group per double bond and may show high acid values due to oxidation during and/or after ozonolysis. Scheme 1.6: Ozonolysis of vegetable oil TAGs to produce polyols[47]. Hydroformylation [70-72], also called oxo synthesis, is another route for producing polyols from vegetable oils. The double bonds in TAGs undergo hydroformylation in the presence of syn gas (a carbon monoxide and hydrogen gas mixture), and suitable catalysts such as rhodium or cobalt, to give the corresponding formylated intermediate. This intermediate is further hydrogenated to give polyol having primary hydroxyl groups [59, 11

37 73]. This method, however, utilizes expensive complex catalysts [70], retains the dangling chains of the omega fatty acids, and like ozonolysis, gives polyols which possess only one OH group per carbon-carbon double bond. Scheme 1.7 shows the hydroformylation reaction of vegetable oil TAGs followed by reduction to produce polyols. Transesterification [67, 74] with glycerol is another method for the synthesis of polyols from vegetable oil based TAGs. Scheme 1.8 shows the synthesis of polyols by transesterification process. Scheme 1.7: Hydroformylation of vegetable oil TAGs to produce polyols. 12

38 Scheme 1.8: Transesterification of vegetable oil TAGs using glycerol to produce polyols Epoxidation [75, 76] of vegetable oils followed by ring opening is a well-established route for the preparation of vegetable oil based polyols. Scheme 1.9 shows the epoxidation of vegetable oil TAGs into the corresponding epoxide and its subsequent ring opening to yield TAG derived polyols. In this method the double bonds are converted into oxirane moieties by treating with peracetic or performic acid formed in situ by the reaction of hydrogen peroxide (H2O2) and acetic acid or formic acid, respectively [75]. Epoxidation followed by acid-catalyzed ring opening using reagents such as HClO4/water allows the conversion of double bonds into two hydroxyl groups per double bond. This is not possible by the synthesis of polyols by ozonolysis or hydroformylation methods. Also, the epoxide groups can be opened using different nucleophilic reagents such as alcohols (R-OH), hydrogen halides (R-X) and thiols (R-SH) to produce differently functionalized polyols having variable OH values [77, 78]. 13

39 Scheme 1.9. Epoxidation reaction of TAG to yield polyol 1.3 Factors Determining the Properties of PU Foams Effect of Polyol Structure The structure and functionality of polyols are very important factors which determine the physical properties of polyurethane foam properties such as compressive strength, thermal stability and glass transition temperature [70]. For example, the molecular weight, hydroxyl value, position of hydroxyl groups and presence of dangling chains of polyols have significant effects on the final properties of the polyurethanes derived from them [56, 59]. It was reported that the glass transition temperatures of the polyurethanes increased to higher temperatures with increasing OH values and, therefore, cross-link density of the polyol [79, 80]. This suggests that the rigidity of the polyurethane foams can be enhanced by increasing the OH value of the polyols. Also, terminal or primary hydroxyl groups 14

40 present in the polyol structure display higher reactivity during polymerization reactions and produce higher crosslinking polymer networks compared to polyols having only nonterminal hydroxyl groups [81]. Polyols having terminal hydroxyls and, therefore, no dangling chains, synthesized from cross metathesized triolein and canola oil, imparted excellent mechanical properties such as higher tensile strength and modulus in polyurethanes compared to soybean oil polyol which possessed dangling chains and only internal hydroxyls [65, 82, 83]. The polyurethane prepared from terminal hydroxyl polyols with no dangling chains behave as rigid plastics having glass transition temperature at 55 ºC [83]. In case of the preparation of rigid polyurethane foams, the addition of primary hydroxyl cross linkers such as glycerine, starch etc. increases the rigidity of the material with more uniform sized cells [52, 69]. Thus, the selection of the synthetic strategies is highly important in order to achieve the necessary architecture in the polyol structure, which imparts essential rigidity to the resulting polyurethanes produced Effect of Isocyanate Like polyols, diisocyanates also contribute significantly to the crosslinking density of PUs. Commercially available aromatic diisocyanates such as MDI (Diphenylmethane diisocyanate) and TDI (Toluenediisocyanate), and aliphatic diisocyanates such as IPDI (Isophorone diisocyanate) and HDI (Hexamethylene diisocyanate), are widely used in the preparation of polyurethane foams [13]. Bio-based lipid diisocyanates synthesized from lipids (oleic acid) have also been used for the preparation of polyurethane thermoplastics with fairly good properties [84, 85]. 15

41 MDI and TDI are the most common diisocyanates that are employed for the preparation of rigid polyurethane foams. It has been shown that polyurethane foams prepared with MDI possess compact and uniformly distributed cells with higher rigidity compared to those prepared with TDI [81]. The high rigidity of MDI based polyurethanes is due to its two aromatic rings and the high molecular weight compared with TDI [52, 81]. Also, the reaction rate with MDI is slower than with TDI [13, 86]. Thus, it allows sufficient time for the formation of a stable three dimensional network that can withstand the pressure of the blowing reaction without the breakage of the foam cells Effect of Catalyst The catalysts used for the polyurethane foaming process play an important role in balancing the blowing and gelling reaction in order to produce desired foams [1]. Without the proper catalyst, competition of the gelling and the blowing reactions occur during foaming, leading to the collapse of the cells in the foams [81]. Polyurethane foaming catalysts are generally amine compounds or organometallic complexes [1, 7]. The catalyst concentration controls the rate of the two competing reactions and by changing the ratio of the catalyst the resulting properties of the polymer foams can be varied. The catalyst amounts should be balanced for the desired gel time, cream time and tack-free time, and significantly affects the cell morphology and the density of the foams [87]. N,N-dimethylbenzylamine (DMBNA) is one of the catalysts widely used for the preparation of polyurethane foams. Tin II caprylate, which is an organo tin catalyst, has been used for rigid polyurethane preparation [52]; increasing the amount of tin II 16

42 caprylate during polymerization enhanced the number of closed cells with decreased gelation time. Dibutyltindilaurate (DBTDL) and N, N-Dimethylethanolamine (DMEA) are the two most common catalysts which are very cheap and widely used in polyurethane foam preparation. DBTDL is a cross linking catalyst which favours the gelling reaction, and DMEA is a co-catalyst which functions as a blowing catalyst during the polymerization process [1, 7]. The appropriate ratios of DBTDL and DMEA is necessary, therefore, to control the foaming process. In most cases both the catalyst and co-catalyst are fixed to the same ratio. Narine et.al, for example, determined that a fixed ratio (1 part by weight) of both DBTDL and DMEA was optimal for the preparation of rigid polyurethane foams of fairly good compressive strength from terminal hydroxyl polyols [68] Effect of Blowing Agent Polyurethane foam production may be aided by the inclusion of a blowing agent in the polymer formulation. The blowing agent promotes the release of a blowing gas which is responsible for the formation of cell voids in the foam. The blowing agent may be a physical blowing agent or a chemical blowing agent. The physical blowing agent is a gas or liquid that does not chemically react with the polyisocyanate composition [7]. A liquid physical blowing agent typically evaporates into a gas when heated, and returns to a liquid when cooled. Such blowing agents are generally inert or they have low reactivity and, therefore, it is likely that they will not decompose or react during the polymerization reaction. The physical blowing agent typically reduces the thermal conductivity of the polyurethane foam [1]. Examples of physical blowing agents 17

43 include carbon dioxide, nitrogen gas, acetone, and low-boiling hydrocarbons such as cyclopentane, isopentane, n-pentane, and their mixtures. Note that the most typical physical blowing agents have a zero ozone depletion potential; blowing agents such as chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), and hydrochlorofluorocarbons (HCFCs) have been used in the past, but these were completely abandoned due to environmental issues [1]. Chemical blowing agents refer to blowing agents which chemically react with the polyisocyanates. Water is the commonly used chemical blowing agent for reaction with polyisocyanates. Increased amount of water content in the polymerization mixture causes expansion of the foam cells and the associated reduction in the thickness of the cell wall [81]. It was observed that with a water content beyond six (6) parts percent by weight, for example, the foaming reaction becomes too rapid and the corresponding foams exhibit poor compressive properties [52], whilst a water content of two (2) parts percent by weight gives optimal compressive strength properties for rigid foams [86] Effect of Surfactant Surfactants are added into the polymer formulation in order to reduce the interfacial tension between the monomers and the aqueous phase [88]. The surfactant controls the size of the foam cells and prevents the collapse of the cells [81]. Silicone based surfactants have been found very effective in producing uniform sized foam cells by creating good air permeability. Polyether-modified polysiloxane (TEGOSTAB B-8404) is one of the widely used silicone surfactant in PU rigid foam formulations [68]. 18

44 1.4 Problems of Vegetable oil Derived PU Foams The unsaturated fatty acids present in vegetable oils possess internal double bonds. Except when ozonolization is used, functionalization of internal double bonds to give polyols retain the omega dangling chains which, upon polymerization, result in incomplete crosslinking and imperfections in the polymer network [23, 89]. This, added to the nonreactive saturated fatty acid already present in the vegetable oil, result in an elevated dangling chain effect which further reduces the polymer rigidity. The regions where dangling chains are present do not support stress when the sample is loaded, and act as plasticizers to reduce polymer rigidity [24, 25]. In fact, the presence of dangling chains and the position of the hydroxyl groups in the fatty acid chain along with the hydroxyl value and molecular weight of the polyol have been cited as the most important structural features which affect the properties of polyurethanes derived from vegetable oils [24, 25, 70, 90]. These issues are generally mitigated through the chemical transformation of the natural oil into a more functional feedstock and judicious choice of methods for synthesizing the polyols [89]. 1.5 Rectification of Dangling Chain Issue Olefin Metathesis Olefin metathesis has been used commercially in the Philips Process for decades now for the conversion of propylene into ethylene and butene [91]. It has been used in the Shell Higher Olefin Process for the production of neohexene for the application of synthetic masks [92, 93]. It has been used since 1972 on TAG oils and unsaturated fatty acid derivatives to produce fine chemicals, substrates and materials, many of which serve as or 19

45 are potential petrochemical replacements [94, 95]. In fact, olefin metathesis holds exceptional promise in oleochemistry for many industries which produce value added monomers from vegetable oils [96-100]; it can be used to increase the molecular diversity and reactivity of natural oils, and, therefore, their potential for transformation into functional materials [101, 102]. Scheme Representation of olefin metathesis reaction [100]. Forward reaction (from left to right) shows the self -metathesis reaction; reverse reaction (from right to left) gives the cross metathesis reaction. Olefin metathesis (Scheme 1.10) is a reversible reaction involving the exchange of the alkylidene groups between the reactant alkene moieties in the presence of catalysts, typically transition metal complexes [100, 103]. Olefin metathesis is categorized further as self-metathesis and cross metathesis [96, 100]. In the self-metathesis reaction (forward reaction in Scheme 1.10), the same olefin molecules react to produce two different olefin products. The self-metathesis of TAGs results in a complex mixture comprising linear oligomers (from dimer to pentamer), macrocyclic structures, cross-linked polymers, as well as trans-/cis isomers [104]. In a cross metathesis reaction (reverse reaction in Scheme 1.10), two different olefins are reacted to produce a new olefin product. Cross-metathesis of a vegetable oil with an olefin results in a metathesized TAG (MTAG) mixture including modified TAG structures not present in the natural oil; for example, carbon-carbon terminal double bond moieties [105, 106]. The actual composition of a metathesis product is highly 20

46 dependent on the reaction conditions, such as starting materials, temperature and type of catalyst. Thus, the product composition of a given metathesis reaction can be controlled by a judicious selection of the reaction conditions [ ]. Cross-metathesis of TAG oils can be used to produce feedstock with increased molecular diversity and reactivity suitable for the production of more functional polyols and, therefore, polyurethanes, as has been demonstrated with triolein [89]. Crossmetathesis, among other modifications, results in low molecular weight metathesized products with terminal double bonds and shortened unsaturated fatty acid moieties [103, 110]. The resulting polyols, therefore, possess terminal hydroxyl groups, facilitating the formation of polyurethane networks with significantly reduced dangling chains compared to natural oil polyols [89]. Ethylene cross-metathesis is one of the cheapest and industrially viable techniques for selective transformation of vegetable oils, but it still has problems related to low yield, poor selectivity and low catalyst turnover due to complicated reaction pathways [99, 100]. For example, the cross-metathesis reaction of crude palm oil with ethylene produces terminal alkene moieties such as 1-decene and 1-heptene, but in low yields [111]. Crossmetathesis with 2-butene, on the other hand, gives high conversions and catalyst turnovers [112, 113]. However, cross-metathesis with the internally unsaturated 2-butene does not give TAG products with terminal carbon-carbon double bonds. Alternately, cross-metathesis with 1-butene will result in a mixture of terminal double bonds and fatty acid moieties with shortened dangling chains (C3) in high yields. In fact, Elevence Renewable Science (ERS) presently uses a protected 1-butene metathesis 21

47 reaction of vegetable oil TAGs to produce 1-decene and 3,4-dodecene [42], whereby the metathesized vegetable oil is a by-product of the biorefinery. This by-product is, therefore, a suitable starting material for the production of bio-based polyols with terminal hydroxyl groups and reduced dangling chain content for use in polyurethane foam production. No such work has been reported so far regarding the study of structure and composition of 1- butene cross metathesized palm oil (PMTAG) and its application for polyols and polyurethane foams Fractionation by Crystallization Since the 1-butene cross-metathesis reaction only modifies the unsaturated fatty acids present in palm oil, the composition of the saturated fatty acids remain unaffected. The non-reactive saturated fatty acids present in the 1-butene metathesized palm oil, however, sterically hinder and lessen the reactivity of the unsaturated fatty acids present in it. The dangling chain action and the steric hindrance of the saturated stearin fraction can be a problem, therefore, in the commercialization of 1-butene metathesized palm oil for the preparation of polyol for the polyurethane industry. In multicomponent systems, the difference in the solubility and solidification of the different components can be exploited for their separation by fractional crystallization [27]. This approach is widely used by the oleochemical industries for the fractionation of edible oils for food and other advanced applications [114]. It is employed to separate the highand low- melting components of edible oils based on their crystallization temperatures [115], which depend on their molecular weight and the degree of the unsaturation. The separated fractions display unique chemical and physical properties. 22

48 Fractionation by crystallization can be further subdivided into dry (neat fractionation) and solvent assisted fractionation (fractionation procedure using solvent) [116]. Solvent assisted fractionation is highly dependent on the solubility of the components in the selected solvent. Solvent assisted crystallization of oils is a fast process and gives good yield while the dry fractionation may require multiple steps for the completion. A large body of literature already exists on the successful fractionation of palm oil to into its high melting (stearin) and low melting (olein) fractions for various food and industrial feedstock applications[ ]. Fractionation by crystallization is, therefore, an established means of reducing the saturated content in the 1-butene metathesized palm oil so as to produce a highly reactive feedstock for polyurethane production. 1.6 Hypotheses The purpose of this study was to convert PMTAG into a useful material for the preparation of the rigid and flexible PU foams and to contribute to the fundamental understanding necessary to address the dangling chain issues of TAGs comprised of omega unsaturated fatty acids. It is expected that the reduction of the dangling chain limitations of palm oil by 1-butene cross metathesis, and the removal of the highly saturated stearin fraction by fractional crystallization will, together, allow for the use of palm oil in rigid polymer applications. The same approach can also be applied to other vegetable oils rich in omega unsaturated fatty acids and saturated fatty acids such as canola and soybean oils, allowing for the preparation of viable bio-based alternatives to petroleum based polyurethanes. The following hypotheses were investigated in this work: 23

49 Hypothesis 1: The terminal hydroxyl PMTAG polyols will produce more rigid polyurethane foams compared to those obtained from palm oil, soybean oil and canola oil. In order to address Hypothesis 1, the following objectives were identified: Establish the structure, chemical composition and physical properties of 1-butene cross metathesized palm oil (PMTAG) Synthesize terminal hydroxyl polyols of maximum OH value from PMTAG by epoxidation followed by hydroxylation procedure. Establish the structure, chemical composition and physical properties of PMTAG polyol. Prepare rigid foams from PMTAG polyols and test their physical properties and compare with palm oil, soybean oil and canola oil derived foams from literature. Hypothesis 2: Flexible foams can be prepared from PMTAG polyol by suitable alteration in the formulation recipe of the rigid foams. In order to address Hypothesis 2, the following objectives were identified: Prepare PU foams from the PMTAG polyol using low catalyst ratio and no glycerine cross linker and test their recovery and compressive strength to check its suitability for flexible foam applications. Hypothesis 3: Fractionation of PMTAG by dry and solvent assisted crystallization will remove the highly saturated stearin fraction (solid fraction) of PMTAG, leaving behind a highly reactive olein fraction (liquid fraction). Polyols derived from the olein fraction of 24

50 PMTAG will possess higher OH values compared to the PMTAG polyol and will make highly rigid foams compared to rigid PMTAG polyol foams. In order to address Hypothesis 3, the following objectives were identified: Fractionate PMTAG using dry and solvent mediated crystallization to separate olein rich and stearin rich fractions. Synthesize polyols from different fractions of PMTAG. Prepare rigid foams from liquid/olein fraction of PMTAG and test their compressive properties, and compare with PMTAG polyol rigid foams. Hypothesis 4: Flexible foams can be prepared from olein fraction (liquid fraction) of PMTAG by varying the formulation recipe. In order to address Hypothesis 4, the following objectives were identified: Prepare PU foams from the liquid fraction PMTAG polyol using low catalyst ratio and no glycerine cross linker and test their recovery and compressive strength to check its suitability for flexible foam applications. Hypothesis 5: Green PMTAG polyols can be prepared by solvent free epoxidation followed by hydroxylation of PMTAG, and their OH values can be controlled by tuning the degree of epoxidation based on the reaction conditions. The rigidity of the Green PMTAG polyol foams will increase with increasing OH value and terminal hydroxyls in the polyol. In order to address Hypothesis 5, the following objectives were identified: 25

51 Synthesize polyols from PMTAG using solvent free pathway of epoxidation and hydroxylation reaction. Control the reaction parameters of epoxidation process to produce polyols with controlled hydroxyl values Prepare flexible foams from Green PMTAG polyols using low catalyst ratio and no glycerine cross linker and test their recovery and compressive strength with flexible PMTAG polyol foams. Prepare rigid foams from Green PMTAG Polyol and compare the rigidity with rigid PMTAG polyol foam. 1.7 Thesis Outline The rest of this thesis is organized into six (6) chapters. Chapter 2 will describe the structure, chemical composition and physical properties of PMTAG and PMTAG polyol. Chapter 3 will describe the preparation and physical characterization of rigid and flexible polyurethane foams prepared from PMTAG polyol (i.e., Hypotheses 1 and 2). Chapter 4 will address the use of dry and solvent mediated fractionation of PMTAG for the effective removal of the highly saturated stearin fraction and the preparation of polyols and polyurethane foams from the fractionated PMTAG (i.e., Hypotheses 3 and 4). Chapter 5 will report on the preparation of green polyols with controlled OH values and their corresponding rigid and flexible foams (i.e., Hypothesis 5). Finally, Chapter 6 will give the conclusion and implications of this work. 26

52 1.8 References [1] Szycher M. Szycher's handbook of polyurethanes: CRC press, [2] Gama NV, Soares B, Freire CS, Silva R, Neto CP, Barros-Timmons A, et al. Bio-based polyurethane foams toward applications beyond thermal insulation. Materials & Design. 2015;76: [3] Babb DA. Polyurethanes from Renewable Resources. In: Rieger B, Kunkel A, Coates GW, Reichardt R, Dinjus E, Zevaco TA, editors. Synthetic Biodegradable Polymers2012. p [4] David J, Vojtová L, Bednařík K, Kučerík J, Vávrová M, Jančář J. Development of novel environmental friendly polyurethane foams. Environmental Chemistry Letters. 2010;8(4): [5]Firm MRCaC. Polymer Foam Market By Types (Polyurethane, Polystyrene, Polyvinyl Chloride, Polyolefin, Phenolic, Melamine and Others), Applications (Packaging, Building & Construction, Furniture & Bedding, Automotive, Wind Energy and Others) & Geography - Global Trends & Forecasts to marketsandmarkets. 2013;CH [6] Firm MRCaC. Polyurethane Foam Market by Type (Flexible Foam, Rigid Foam), by End-User Industry (Bedding & Furniture, Building & Construction, Electronics, Automotive, Footwear, Packaging, Others), by Geography - Global Trends & Forecasts to 2020.marketsandmarkets.2015( ethane-foams.asp.). 27

53 [7] Ashida K. Polyurethane and related foams: chemistry and technology: CRC press, [8] Desroches M, Escouvois M, Auvergne R, Caillol S, Boutevin B. From vegetable oils to polyurethanes: synthetic routes to polyols and main industrial products. Polymer Review. 2012;52(1): [9] Zhang C, Madbouly SA, Kessler MR. Biobased polyurethanes prepared from different vegetable oils. ACS applied materials & interfaces. 2015;7(2): [10] Lligadas G, Ronda JC, Galia M, Cádiz V. Plant oils as platform chemicals for polyurethane synthesis: current state-of-the-art. Biomacromolecules. 2010;11(11): [11] Samarth NB, Mahanwar PA. Modified Vegetable Oil Based Additives as a Future Polymeric Material Review. Open Journal of Organic Polymer Materials. 2015;5(01):1. [12] Zhang L, Jeon HK, Malsam J, Herrington R, Macosko CW. Substituting soybean oilbased polyol into polyurethane flexible foams. Polymer. 2007;48(22): [13] Tan S, Abraham T, Ference D, Macosko CW. Rigid polyurethane foams from a soybean oil-based polyol. Polymer. 2011;52(13): [14] Ji D, Fang Z, He W, Luo Z, Jiang X, Wang T, et al. Polyurethane rigid foams formed from different soy-based polyols by the ring opening of epoxidised soybean oil with methanol, phenol, and cyclohexanol. Industrial Crops and Products. 2015;74:

54 [15] Ji D, Fang Z, He W, Zhang K, Luo Z, Wang T, et al. Synthesis of soy-polyols using a continuous micro-flow system and preparation of soy-based polyurethane rigid foams. ACS Sustainable Chemistry & Engineering [16] Zhang L, Zhang M, Hu L, Zhou Y. Synthesis of rigid polyurethane foams with castor oil-based flame retardant polyols. Industrial Crops and Products. 2014;52: [17] Khoe TH, Otey FH, Frankel EN. Rigid urethane foams from hydroxymethylated linseed oil and polyol esters. Journal of the American Oil Chemists' Society. 1972;49(11): [18] Calvo-Correas T, Mosiewicki MA, Corcuera MA, Eceiza A, Aranguren MI. Linseed Oil-Based Polyurethane Rigid Foams: Synthesis and Characterization. Journal of Renewable Materials. 2015;3(1):3-13. [19] Hu YH, Gao Y, Wang DN, Hu CP, Zu S, Vanoverloop L, et al. Rigid polyurethane foam prepared from a rape seed oil based polyol. Journal of Applied Polymer Science. 2002;84(3): [20] Mosiewicki MA, Rojek P, Michałowski S, Aranguren MI, Prociak A. Rapeseed oilbased polyurethane foams modified with glycerol and cellulose micro/nanocrystals. Journal of Applied Polymer Science. 2015;132(10). [21] Michałowski S, Prociak A. Flexible Polyurethane Foams Modified with New Bio- Polyol Based on Rapeseed Oil. Journal of Renewable Materials. 2015;3(1):

55 [22] Babb DA. Polyurethanes from renewable resources. Synthetic Biodegradable Polymers: Springer; p [23] Narine SS, Kong X, Bouzidi L, Sporns P. Physical properties of polyurethanes produced from polyols from seed oils: II. Foams. Journal of the American Oil Chemists' Society. 2007;84(1): [24] Narine SS, Yue J, Kong X. Production of polyols from canola oil and their chemical identification and physical properties. Journal of the American Oil Chemists' Society. 2007;84(2): [25] Zlatanic A, Petrovic ZS, Dusek K. Structure and properties of triolein-based polyurethane networks. Biomacromolecules. 2002;3(5): [26] Nagendran B, Unnithan U, Choo Y, Sundram K. Characteristics of red palm oil, a carotene-and vitamin E rich refined oil for food uses. Food & Nutrition Bulletin. 2000;21(2): [27] Gunstone F. Vegetable oils in food technology: composition, properties and uses: John Wiley & Sons, [28] Lida H, Sundram K, Siew WL, Aminah A, Mamot S. TAG composition and solid fat content of palm oil, sunflower oil, and palm kernel olein blends before and after chemical interesterification. Journal of the American Oil Chemists Society. 2002;79(11): [29] Edem D. Palm oil: Biochemical, physiological, nutritional, hematological and toxicological aspects: A review. Plant Foods for Human Nutrition. 2002;57(3-4):

56 [30] Santosa SJ. Palm oil boom in Indonesia: from plantation to downstream products and biodiesel. CLEAN Soil, Air, Water. 2008;36(5 6): [31] Ong A, Goh S. Palm oil: a healthful and cost-effective dietary component. Food & Nutrition Bulletin. 2002;23(1): [32] Tanaka R, Hirose S, Hatakeyama H. Preparation and characterization of polyurethane foams using a palm oil-based polyol. Bioresource Technology. 2008;99(9): [33] Ogoshi T, Miyawaki Y. Soap and related products: Palm and lauric oil. Journal of the American Oil Chemists Society. 1985;62(2): [34] Chang T-S, Yunus R, Rashid U, Choong TS, Awang Biak DR, Syam AM. Palm Oil Derived Trimethylolpropane Triesters Synthetic Lubricants and Usage in Industrial Metalworking Fluid. Journal of oleo science. 2015(0). [35] Shomchoam B, Yoosuk B. Eco-friendly lubricant by partial hydrogenation of palm oil over Pd/γ-Al 2 O 3 catalyst. Industrial Crops and Products. 2014;62: [36] Abu-Hamdeh NH, Alnefaie KA. A comparative study of almond and palm oils as two bio-diesel fuels for diesel engine in terms of emissions and performance. Fuel. 2015;150: [37] Tulathammakit H, Kitiyanan B. Synthesis of Methyl Ester Sulphonate Surfactant from Palm Oil Methyl Ester by Using UV or Ozone as an Initiator. CHEMICAL ENGINEERING. 2014;39. 31

57 [38] Chuayjuljit S, Sangpakdee T, Saravari O. Processing and properties of palm oil-based rigid polyurethane foam. Journal of The Minerals, Metals & Materials Society. 2007;17:7-23. [39] Lee C, Ooi T, Chuah C, Ahmad S. Rigid polyurethane foam production from palm oil-based epoxidized diethanolamides. Journal of the American Oil Chemists Society. 2007;84(12): [40] Pawlik H, Prociak A. Influence of palm oil-based polyol on the properties of flexible polyurethane foams. Journal of Polymers and the Environment. 2012;20(2): [41] Grubbs RH, O'Leary DJ. Handbook of metathesis: Applications in organic synthesis: John Wiley & Sons, [42] Schrodi Y, Pederson RL, Kaido H, Tupy MJ. Synthesis of terminal alkenes from internal alkenes via olefin metathesis. Google Patents; [43] Guan J, Song Y, Lin Y, Yin X, Zuo M, Zhao Y, et al. Progress in study of nonisocyanate polyurethane. Industrial & Engineering Chemistry Research. 2011;50(11): [44] More AS, Gadenne B, Alfos C, Cramail H. AB type polyaddition route to thermoplastic polyurethanes from fatty acid derivatives. Polymer Chemistry. 2012;3(6): [45] Oertel G. Polyurethane Handbook,(1993), Hanser. Gardner Publications, Inc., Cincinnati, OH. 32

58 [46] Narine SS, Kong X, Bouzidi L, Sporns P. Physical properties of polyurethanes produced from polyols from seed oils: I. Elastomers. Journal of the American Oil Chemists Society. 2007;84(1): [47] Kong X, Narine SS. Physical properties of polyurethane plastic sheets produced from polyols from canola oil. Biomacromolecules. 2007;8(7): [48] Somani KP, Kansara SS, Patel NK, Rakshit AK. Castor oil based polyurethane adhesives for wood-to-wood bonding. International Journal of Adhesion and Adhesives. 2003;23(4): [49] Velayutham TS, Majid WHA, Ahmad AB, Kang GY, Gan SN. Synthesis and characterization of polyurethane coatings derived from polyols synthesized with glycerol, phthalic anhydride and oleic acid. Progress in Organic Coatings. 2009;66(4): [50] Bernal MM, Lopez-Manchado MA, Verdejo R. In situ Foaming Evolution of Flexible Polyurethane Foam Nanocomposites. Macromolecular Chemistry and Physics. 2011;212(9): [51] Harikrishnan G, Khakhar DV. Effect of monomer temperature on foaming and properties of flexible polyurethane foams. Journal of Applied Polymer Science. 2007;105(6): [52] John J, Bhattacharya M, Turner RB. Characterization of polyurethane foams from soybean oil. Journal of Applied Polymer Science. 2002;86(12):

59 [53] Ugarte L, Saralegi A, Fernández R, Martín L, Corcuera M, Eceiza A. Flexible polyurethane foams based on 100% renewably sourced polyols. Industrial Crops and Products. 2014;62: [54] Piszczyk Ł, Strankowski M, Danowska M, Hejna A, Haponiuk JT. Rigid polyurethane foams from a polyglycerol-based polyol. European Polymer Journal. 2014;57: [55] Malewska E, Bąk S, Prociak A. Effect of different concentration of rapeseed oil based polyol and water on structure and mechanical properties of flexible polyurethane foams. Journal of Applied Polymer Science. 2015;132(35). [56] Ionescu M. Chemistry and technology of polyols for polyurethanes: ismithers Rapra Publishing, [57] Gunstone F. The chemistry of oils and fats: sources, composition, properties and uses: John Wiley & Sons, [58] Kamal-Eldin A, Andersson R. A multivariate study of the correlation between tocopherol content and fatty acid composition in vegetable oils. Journal of the American Oil Chemists Society. 1997;74(4): [59] Petrovic ZS, Guo A, Javni I, Cvetkovic I, Hong DP. Polyurethane networks from polyols obtained by hydroformylation of soybean oil. Polymer International. 2008;57(2):

60 [60] Biermann U, Friedt W, Lang S, Lühs W, Machmüller G, Metzger JO, et al. New syntheses with oils and fats as renewable raw materials for the chemical industry. Angewandte Chemie International Edition. 2000;39(13): [61] Veronese VB, Menger RK, Forte MMdC, Petzhold CL. Rigid polyurethane foam based on modified vegetable oil. Journal of Applied Polymer Science. 2011;120(1): [62] Narine SS, Yue J, Kong XH. Production of polyols from canola oil and their chemical identification and physical properties. Journal of the American Oil Chemists Society. 2007;84(2): [63] Barrett L, Sperling L, Murphy C. Naturally functionalized triglyceride oils in interpenetrating polymer networks. Journal of the American Oil Chemists Society. 1993;70(5): [64] Guner FS, Yagci Y, Erciyes AT. Polymers from triglyceride oils. Progress in Polymer Science. 2006;31(7): [65] Petrović ZS, Zhang W, Javni I. Structure and Properties of Polyurethanes Prepared from Triglyceride Polyols by Ozonolysis. Biomacromolecules. 2005;6(2): [66] Wan Nik W, Ani FN, Masjuki H. Thermal stability evaluation of palm oil as energy transport media. Energy Conversion and Management. 2005;46(13): [67] Arniza M, Hoong S, Idris Z, Yeong S, Hassan H, Din A, et al. Synthesis of Transesterified Palm Olein-Based Polyol and Rigid Polyurethanes from this Polyol. Journal of the American Oil Chemists Society. 2015;92(2):

61 [68] Narine S, Kong X, Bouzidi L, Sporns P. Physical Properties of Polyurethanes Produced from Polyols from Seed Oils: II. Foams. Journal of the American Oil Chemists Society. 2007;84(1): [69] Guo A, Zhang W, Petrovic ZS. Structure-property relationships in polyurethanes derived from soybean oil. Journal of Materials Science. 2006;41(15): [70] Guo A, Demydov D, Zhang W, Petrovic ZS. Polyols and Polyurethanes from Hydroformylation of Soybean Oil. Journal of Polymers and the Environment. 2002;10(1): [71] Kandanarachchi P, Guo A, Petrovic Z. The hydroformylation of vegetable oils and model compounds by ligand modified rhodium catalysis. Journal of Molecular Catalysis A: Chemical. 2002;184(1 2): [72] Petrovic ZS. Polyurethanes from vegetable oils. Polymer Review. 2008;48(1): [73] Khoe T, Otey F, Frankel E. Rigid urethane foams from hydroxymethylated linseed oil and polyol esters. Journal of the American Oil Chemists Society. 1972;49(11): [74] Zlatanić A, Javni I, Ionescu M, Bilić N, Petrović ZS. Polyurethane molded foams with high content of hyperbranched polyols from soybean oil. Journal of Cellular Plastics. 2014: X [75] Tan SG, Chow WS. Biobased Epoxidized Vegetable Oils and Its Greener Epoxy Blends: A Review. Polymer-Plastics Technology and Engineering. 2010;49(15):

62 [76] Chen R, Zhang C, Kessler MR. Polyols and polyurethanes prepared from epoxidized soybean oil ring opened by polyhydroxy fatty acids with varying OH numbers. Journal of Applied Polymer Science. 2015;132(1). [77] Adhvaryu A, Liu Z, Erhan S. Synthesis of novel alkoxylated triacylglycerols and their lubricant base oil properties. Industrial Crops and Products. 2005;21(1): [78] Pawlik H, Prociak A, Pielichowski J. Synteza polioli z oleju palmowego przeznaczonych do otrzymywania elastycznych pianek poliuretanowych. Czasopismo Techniczne Chemia. 2009;106: [79] Wang C-S, Yang L-T, Ni B-L, Shi G. Polyurethane networks from different soy-based polyols by the ring opening of epoxidized soybean oil with methanol, glycol, and 1,2- propanediol. Journal of Applied Polymer Science. 2009;114(1): [80] Pechar TW, Sohn S, Wilkes GL, Ghosh S, Frazier CE, Fornof A, et al. Characterization and comparison of polyurethane networks prepared using soybean-based polyols with varying hydroxyl content and their blends with petroleum-based polyols. Journal of Applied Polymer Science. 2006;101(3): [81] Campanella A, Bonnaillie LM, Wool RP. Polyurethane Foams from Soyoil-Based Polyols. Journal of Applied Polymer Science. 2009;112(4): [82] Dumont MJ, Narine SS. Physical Properties of New Polyurethanes Foams from Benzene Polyols Synthesized from Erucic Acid. Journal of Applied Polymer Science. 2010;118(6):

63 [83] Petrovic ZS, Zhang W, Javni I. Structure and properties of polyurethanes prepared from triglyceride polyols by ozonolysis. Biomacromolecules. 2005;6(2): [84] Hojabri L, Kong XH, Narine SS. Novel Long Chain Unsaturated Diisocyanate from Fatty Acid: Synthesis, Characterization, and Application in Bio-Based Polyurethane. Journal of Polymer Science Part a-polymer Chemistry. 2010;48(15): [85] Hojabri L, Kong XH, Narine SS. Fatty Acid-Derived Dilsocyanate and Biobased Polyurethane Produced from Vegetable Oil: Synthesis, Polymerization, and Characterization. Biomacromolecules. 2009;10(4): [86] Guo A, Javni I, Petrovic Z. Rigid polyurethane foams based on soybean oil. Journal of Applied Polymer Science. 2000;77(2): [87] Choe KH, Lee DS, Seo WJ, Kim WN. Properties of rigid polyurethane foams with blowing agents and catalysts. Polymer journal. 2004;36(5): [88] Zhang XD, Macosko CW, Davis HT, Nikolov AD, Wasan DT. Role of silicone surfactant in flexible polyurethane foam. Journal of Colloid and Interface Science. 1999;215(2): [89] Zlatanić A, Petrović ZS, Dušek K. Structure and Properties of Triolein-Based Polyurethane Networks. Biomacromolecules. 2002;3(5): [90] BUDINSKI-SIMENDIC J, SPIRKOVA M, PAVLICEVIC J, SOMVARSKY J, MESZAROS SZECSENYI K, DUSEK K. Structure and Properties of Dangling Chain Poly (urethane-isocyanurate) Model Network. Conference Structure and Properties of Dangling 38

64 Chain Poly (urethane-isocyanurate) Model Network, vol Oxford University Press, p [91] Mol J. Industrial applications of olefin metathesis. Journal of Molecular Catalysis A: Chemical. 2004;213(1): [92] Keim W. Oligomerization of Ethylene to α Olefins: Discovery and Development of the Shell Higher Olefin Process (SHOP). Angewandte Chemie International Edition. 2013;52(48): [93] Lutz E. Shell higher olefins process. Journal of Chemical Education. 1986;63(3):202. [94] Van Dam P, Mittelmeijer M, Boelhouwer C. Metathesis of unsaturated fatty acid esters by a homogeneous tungsten hexachloride tetramethyltin catalyst. Journal of the Chemical Society, Chemical Communications. 1972(22): [95] Nickel A, Ung T, Mkrtumyan G, Uy J, Lee C, Stoianova D, et al. A Highly Efficient Olefin Metathesis Process for the Synthesis of Terminal Alkenes from Fatty Acid Esters. Top Catal. 2012;55(7-10): [96] Mol JC, Buffon R. Metathesis in oleochemistry. Journal of the Brazilian Chemical Society. 1998;9(1):1-11. [97] Patel J, Elaridi J, Jackson WR, Robinson AJ, Serelis AK, Such C. Cross-metathesis of unsaturated natural oils with 2-butene. High conversion and productive catalyst turnovers. Chemical Communications. 2005(44):

65 [98] Rybak A, Fokou PA, Meier MAR. Metathesis as a versatile tool in oleochemistry. European Journal of Lipid Science and Technology. 2008;110(9): [99] Thomas RM, Keitz BK, Champagne TM, Grubbs RH. Highly selective ruthenium metathesis catalysts for ethenolysis. Journal of the American Chemical Society. 2011;133(19): [100] Malacea R, Dixneuf PH. Alkene Metathesis and Renewable Materials: Selective Transformations of Plant Oils. Green Metathesis Chemistry: Springer; p [101] Peng G. Novel biosurfactants by ring-opening cross-metathesis. European Journal of Lipid Science and Technology. 2015;117: [102] Chikkali S, Mecking S. Refining of plant oils to chemicals by olefin metathesis. Angewandte Chemie International Edition. 2012;51(24): [103] Connon SJ, Blechert S. Recent developments in olefin cross metathesis. Angewandte Chemie International Edition. 2003;42(17): [104] Refvik M, Larock R. The chemistry of metathesized soybean oil. Journal of Applied Polymer Science. 1999;76(1): [105] Zlatanic A, Petrovic ZS, Dušek K. Structure and properties of triolein-based polyurethane networks. Biomacromolecules. 2002;3(5): [106] Rosenburg DW. To produce reduced chain length esters and alpha-olefins. Google Patents;

66 [107] Li SJ, Hojabri L, Narine SS. Controlling Product Composition of Metathesized Triolein by Reaction Concentrations. Journal of Applied Polymer Science 2012;89(11): [108] Tian QP, Larock RC. Model studies and the ADMET polymerization of soybean oil. Journal of Applied Polymer Science. 2002;79(5): [109] Biermann U, Metzger JO, Meier MAR. Acyclic Triene Metathesis Oligo- and Polymerization of High Oleic Sun Flower Oil. Macromolecular Chemistry and Physics. 2010;211(8): [110] Mol J. Catalytic metathesis of unsaturated fatty acid esters and oils. Top Catal. 2004;27(1-4): [111] Ahmad F, Hamdan S, Yarmo M, Alimunir A. Co-metathesis reaction of crude palm oil and ethene. Journal of the American Oil Chemists Society. 1995;72(6): [112] Patel J, Mujcinovic S, Jackson WR, Robinson AJ, Serelis AK, Such C. High conversion and productive catalyst turnovers in cross-metathesis reactions of natural oils with 2-butene. Green Chemistry. 2006;8(5): [113] RoyáJackson W. Cross-metathesis of unsaturated natural oils with 2-butene. High conversion and productive catalyst turnovers. Chemical communications. 2005(44): [114] Hamm W. Trends in edible oil fractionation. Trends in Food Science & Technology. 1995;6(4):

67 [115] Gibon V. Palm oil and palm kernel oil refining and fractionation technology. Palm oil: production, processing, characterization, and uses AOCS Press, Urbana. 2012: [116] Kellens M, Gibon V, Hendrix M, De Greyt W. Palm oil fractionation. European Journal of Lipid Science and Technology. 2007;109(4): [117] Koay GF, Chuah T-G, Choong TS. Economic feasibility assessment of one and two stages dry fractionation of palm kernel oil. Industrial Crops and Products. 2013;49: [118] Deffense E. Fractionation of palm oil. Journal of the American Oil Chemists Society. 1985;62(2): [119] Hasmadi M, AINI I, Mamot S, Yusof M. The effect of different types of stirrer and fractionation temperatures during fractionation on the yield, characteristics and quality of oleins. Journal of Food Lipids. 2002;9(4):

68 2 1-Butene Metathesized Palm Oil & Polyol Derivatives: Structure, Chemical Composition and Physical Properties 2.1 Introduction Growing concerns surrounding sustainability, biodegradability, control of CO2 emission and other environmental problems are driving a strong demand for alternatives to petroleum as a feedstock for fuels and materials. Vegetable oils are advantageous in this regard because of their availability in large quantities, renewability and relative low cost [1]. Furthermore, their triacylglycerol (TAG) structure is attractive for the chemical industry as it offers ready sites, such as the double bond and the ester, for chemical transformation [2]. There currently exists an important oleochemical industry that uses a large array of standard as well as novel chemical reactions on TAG oils to make a variety of fine chemicals and materials such as fuels, polymers, lubricants, waxes and cosmetics [3-5]. The development of polyurethanes from renewable and environment-friendly feedstock is of particular importance as the market is very large and growing due to high demand across industries such as automotive, building and construction, and packaging. The worth of the global polymer foams market was $82.6 billion in 2012 and is estimated to reach $131.1 billion by 2018 [6]. A relatively large body of literature reporting on the synthesis of polyols and polyurethanes from natural oils is available (see for example PU foams from soybean oil [7, 8], safflower oil, corn oil, sunflower seed oil, linseed oil [9], rapeseed oil [10], palm oil [11], cotton seed oil [12]). 43

69 However, the development of polyol substrates and PU foams from natural oils is challenging. The introduction of hydroxyl groups at the positions of double bonds can be achieved by various methods [3]. Some of the methods are ozonolysis followed by hydrogenation [13, 14], hydroformylation followed by hydrogenation [4, 15], epoxidation followed by ring opening [16, 17] or bioconversion directly to polyols [18]. These synthesis methods produce polyols of distinctive hydroxyl value, distribution and position of the hydroxyl groups which result in polyurethane networks with vastly different properties [14, 15, 19]. In many instances however, the functionalization of the double bonds leaves significant amounts of dangling chains because of their internal location on the fatty acids. The presence of relatively large amounts of non-reactive moieties further reduce the suitability of the polyols, especially to make rigid polyurethane foams because the regions where dangling chains are present do not support stress when the sample is loaded, and act as plasticizers that reduce polymer rigidity. These issues are generally mitigated through the chemical transformation of the natural oil and judicious choice of methods of synthesizing the polyols [20]. Palm oil is a particularly important TAG oil. It is the most produced and one of the cheapest renewable commodity oils in the world, making it an ideal feedstock replacement at an industrial scale. It is primarily used in foods [5, 21] and increasingly sought for the production of industrial materials. Palm oil is typically composed of 95% TAGs and 5% diacylglycerols (DAGs) and other minor components such as monoacylglycerols (MAGs) with a fatty acid profile ranging typically from C12 to C20 [22, 23]. It has a balanced saturation (~50/50 % of saturates / unsaturates) [24, 25]. Palmitic acid (P, C16:0) and oleic acid (O, C18:1) with ~43% and ~41%, respectively, are the main components of palm oil. 44

70 Palm oil includes ~10% linoleic acid (Li, C18:2), and trace amounts of linolenic acid (Ln, C18:3) and palmitoleic acid (C16:1). Other representative saturated fatty acids in palm oil are lauric acid (L, C12:0), myristic acid (M, C14:0), stearic acid (S, C18:0) and arachidic acid (A, C20:0). The TAG profile of palm oil shows a carbon distribution of C46 to C52 consisting of tri-unsaturated ( %), di-unsaturated ( %), mono unsaturated ( %) and saturated TAGs [5]. Despite high saturation, palm oil has been successfully transformed into a variety of industrial materials [26]. It is increasingly used to make value added products such as soaps and detergents [27], lubricants [28, 29], biodiesel [24, 30] and surfactant [31], etc. Palm oil and its derivatives are also actively investigated as a feedstock for the synthesis of polyols to prepare polyurethanes [11, 26, 32]. However, its larger use for the production of polyurethanes is hindered because of its relatively higher saturation level (50% fatty acids) which cap the hydroxyl value of its polyols, which adds to the structural limitations inherent to TAG oils [22]. Typical palm oil-based polyols produced so far usually have hydroxyl values of less than 200 mg KOH g 1 [33] limiting their applicability in some polymer formulations, particularly in rigid polyurethane foams. Although some successful examples through chemical transformation of the natural oil are reported in the literature, such as for example, the transformation of the TAGs of the natural palm oil into monoacylglycerols (MAG) before functionalization and polymerization [26, 34], no significant breakthroughs have been made with palm oil in this area. More research around the transformation of the natural oil such as targeted chemistry and proper processing techniques, is needed to increase the potential of palm oil as a viable source for polyols and polyurethane formulations. Olefin metathesis is a very powerful 45

71 transformation technology adopted by our research group that promises to be one of the platforms that can be used on palm oil and other vegetable oils to achieve this goal. It is an important organic synthesis technique that holds exceptional promise in oleochemistry for many industries. It is already used on TAG oils and fats to produce fine chemicals, substrates and materials, many of which serve as or are potential petrochemical replacements [35-38]. Olefin metathesis can increase the molecular diversify and reactivity of the natural oil, and therefore the potential for its transformation into functional materials. Olefin metathesis (Scheme 2.1) is a reversible reaction involving the exchange of the alkylidene groups between the reactant alkene moieties in the presence of catalysts, typically transition metal complexes [38, 39]. Scheme 2.1. Representation of olefin metathesis reaction. Olefin metathesis is categorized further as self-metathesis and cross metathesis [36, 38]. In the self-metathesis reaction (forward reaction in Scheme 2.1) the same olefin molecules react to produce two different olefin products. The self-metathesis of TAGs results in a complex mixture comprising linear oligomers (from dimer to pentamer), macrocyclic structures, cross-linked polymers, as well as trans-/cis isomers [40]. In a cross metathesis reaction (backward reaction in Scheme 2.1) two different olefins are reacted to produce a new olefin product. Cross-metathesis of a vegetable oil with olefins results in a metathesized TAG (MTAG) mixture including modified TAG structures, such as terminal double bonds, not present in the natural oil [41, 42]. The actual composition of a metathesis product is highly dependent on the reaction conditions, such as starting materials, 46

72 temperature, type of catalyst, etc., which provides the possibility of controlling the product composition [43-45]. The cross-metathesis of a TAG oil can be used to produce a feedstock with increased molecular diversity and reactivity suitable for the production of more functional polyols and polyurethanes as demonstrated with triolein [20]. The reaction, among other modifications, shortens some of the unsaturated fatty acids at the location of the double bond producing low molecular weight metathesized products with terminal double bonds, offering less steric hindrance and in some cases increased reactivity [39, 46]. Because of its low molecular weight and terminal double bond structure, the cross metathesized TAG can produce polyols with terminal hydroxyl groups and therefore polyurethane networks with dramatically reduced dangling chains [20]. Cross-metathesis reaction of crude palm oil with ethylene produced terminal alkenes such as: 1-decene and 1-heptene in low yield [47]. Ethylene cross metathesis is one of the cheapest and most industrially viable techniques for selective transformation of vegetable oils, but it still has problems related to low yield, poor selectivity and low catalyst turnover due to complicated reaction pathways [37, 38]. The modified TAG byproduct obtained via 1-butene cross metathesis of palm oil contains similar terminal structures as those from ethylene cross metathesis, that can be used as valuable materials to produce polyols without dangling chain. The composition and the properties of the modified palm oil TAG from 1- butene metathesis have not been fully understood. The present work reports on the characterisation of the chemistry, structure, and physical properties of the product of the cross-metathesis of palm oil with 1-butene 47

73 (butenolysis) stripped from its olefins (referred to in the text by PMTAG) and the synthesis of polyols from PMTAG. The uniqueness of the structure of the transformed material compared to the natural oil is highlighted and its potential for the production of value added products is assessed. Note that high conversion and productive catalyst turnover were achieved similarly to what was reported with similar synthetic routes, such as 2- butene cross metathesis of plant oils [48, 49]. PMTAG was provided by our industry partner, Elevence Renewable Sciences (ERS, Bolingbrook, Ill., USA), who first introduced the technique [50]. It is in fact the by-product of the industrial biorefinery that produces 1-decene and 3,4-dodecene linear aliphatic olefins for the fine chemicals sector. ERS currently operate a biorefinery plant in Indonesia that processes 400 million lbs. of palm oil annually, with advanced plans to build other biorefinery processing plants in North America that will utilize cross-metathesis on native plant oils such as soybean oil and canola oil. The transformation of the by-product into polyols (and other chemicals) as demonstrated has the potential to increase the profitability of the bio-refineries dramatically. The polyol was synthesized by the epoxidation of the PMTAG using hydrogen peroxide (H2O2) and formic acid followed by ring opening reaction with H2O and HClO4. This is a well-established economical route to produce polyols. In this method the double bonds are converted into oxirane moieties and the epoxy groups are converted into hydroxyl groups by ring opening reaction with suitable reagents like HClO4 and H2O to give the polyol [51]. The reaction parameters (solvents type, time and temperature) were optimized in order to produce the most economical and functional polyol. 48

74 The chemical structure and chemical composition of PMTAG and PMTAG Polyol were determined by 1 H-NMR, GC, MS and HPLC. Their thermal degradation, thermal transformation behavior and flow properties were characterized with TGA, DSC, and rotational rheometry, respectively. 2.2 Materials and Methods Materials PMTAG is one of the products of the cross-metathesis of palm oil and 1-butene which was stripped of olefins and provided by ERS. Ethanol (anhydrous), toluene, potassium hydroxide, and sodium thiosulfate were purchased from ACP chemical Inc. (Montreal, Quebec, Canada) and were used without further treatment. Iodine monochloride (95%), potassium iodide (99%), and phenolphthalein were purchased from Sigma-Aldrich Canada Co. (Oakville, Ontario, Canada). The general materials for PMTAG polyol synthesis were: formic acid (88 wt %), hydrogen peroxide (H2O2) solution (30 wt %) purchased from Sigma-Aldrich, Canada, perchloride acid (70%) from Fisher Scientific, Canada, hexanes (Hx), dichloromethane (DCM), ethyl acetate (EA) and tetrahydrofuran (THF) from ACP chemical Int. (Montreal, Quebec, Canada). All were used without further treatment Chemistry characterization techniques Titrimetric Methods (OH value, Acid value and Iodine value) Iodine and acid values were determined according to ASTM D and ASTM D , respectively. Hydroxyl value was determined according to ASTM D

75 Nuclear magnetic resonance (NMR) 1 H-NMR spectra of PMTAG and PMTAG Polyol were recorded in CDCl3 as solvent on a Varian Unity-INOVA (McKinley Scientific, USA) at MHz. The spectra were obtained using an 8.6 μs pulse with 4 transients collected in points. Datasets were zero-filled to points, and a line broadening of 0.4 Hz was applied prior to Fourier transformation. Chemical shifts were referenced relative to residual solvent peaks (7.26 ppm). The spectra were processed using spinwork NMR Processor, version Mass spectrometry (MS) Electrospray Ionisation Mass Spectrometry (ESI-MS) analysis of PMTAG Polyol was performed on a QStar XL quadrupole time-of-flight mass spectrometer (AB Sciex, Concord, ON) equipped with an ionspray source and modified hot source-induced desolvation (HSID) interface (Ionics, Bolton, ON). The ion source and interface conditions were adjusted as follows: ionspray voltage (IS) = 4500 V, nebulising gas (GS1) = 45, curtain gas (GS2) = 45, declustering potential (DP) = 60 V and HSID temperature (T) = 200 C. Multiply-charged ion signals were reconstructed using the BioTools software High pressure liquid chromatography (HPLC) HPLC was performed on an e2695 HPLC system (Waters Corporation, Milford, MA, USA) fitted with a Waters ELSD 2424 evaporative light scattering detector. The HPLC was equipped with an inline degasser, a pump and an auto-sampler. The ELSD nitrogen flow was set at 25 psi with nebulization and drifting tube maintained at 12 ºC and 55 ºC, respectively. Gain was set at

76 A slow method was used for the HPLC analysis of PMTAG. The analysis was performed with an X-Bridge column (C18, 150mm 4.6 mm, 5.0 µm, X-Bridge column, Waters Corporation, MA, and Superspher 100 RP-18, 250mm 4.0 mm, Thermo Science)in series with Superspher 100 RP-18 column (250 mm 4.0 mm, from Thermo Scientific, Waltham, MA, USA) both at 30 ºC. The sample (4 L) was passed through the columns by reversed phase in isocratic mode. The mobile phase (2-propanol: acetonitrile: heptane (38:57:5)v) was run for 120 min at a flow rate of 0.5 ml/min. For the analysis of PMTAG polyol, a Betasil diol column (250mm 4.0 mm, 5.0 µm) was used at 50 ºC. The sample (4 L) was run in normal phase and in gradient elution mode. The mobile phase was started with heptane: ethyl acetate ratio of (90:10)v run for 1 min at a flow rate of 1 ml/min, then (67:33)v in 55 min. The ratio of ethyl acetate was increased to 100% in 20 min and then held for 10 min. In both cases, 5 mg/ml (w/v) solution of crude sample in heptane was filtered through a filter vial (Thomson Instrument Company, Oceanside, CA). All solvents were HPLC grade and obtained from VWR International (Mississauga, ON, Canada). Waters Empower Version 2 software was used for data collection and data analysis. Purity of eluted samples was determined using the relative peak area Gas chromatography (GC) GC of PMTAG was performed by ERS on an Agilent 7890 equipped with a split/splitless inlet. The splitter was connected to two detectors: a flame ionization detector (FID) and Agilent 5975C mass selective detector (MSD) via deactivated guard columns. The length of the guard column to the FID was 0.5 m and 5.0 m to the MSD. The column 51

77 used for the analysis was a Restek Rtx-65TG capillary column (Crossbond 65% diphenyl / 35% dimethyl polysiloxane; 30 m 0.25 mm 0.1 µm df). One microliter of the sample was injected using a LEAP Technologies Combi-PAL autosampler equipped with a 10 µl syringe Physical characterization techniques Thermogravimetric analysis (TGA) TGA of PMTAG and PMTAG Polyol was carried out on a TGA Q500 (TA Instruments, DE, USA). Approximately mg of sample was loaded in the open TGA platinum pan. The sample was equilibrated at 25 C and then heated to 600 C at a constant rate of 10 C/min. The TGA measurements were performed under dry nitrogen of 40 ml/min for balance purge flow and 60 ml/min for sample purge flow Differential Scanning Calorimetry (DSC) DSC measurements of PMTAG and PMTAG Polyol were performed in the standard mode on a Q200 model (TA Instruments) under a nitrogen flow of 50 ml/min. The sample (3.5 to 6.5 ± 0.1 mg) in hermetically sealed aluminum DSC pans was equilibrated at 90 C for 10 min to erase thermal memory, and then cooled at a constant rate (5.0 C/min) to -90 C where it was held isothermally for 5 min, and subsequently reheated at 5.0 C/min to 90 C. TA Universal Analysis software was used to analyze the TGA and DSC data and extract the crystallization and melting characteristics. Non-resolved peaks were analyzed with the help of the first and second derivatives of the differential heat flow. The measurement temperatures are reported to a certainty of better than ± 0.5 C. 52

78 Rheology The flow behavior and viscosity versus temperature of PMTAG and PMTAG Polyol were measured on a temperature controlled Rheometer (AR2000ex) using a 40-mm, 2 steel geometry. Temperature control was achieved by Peltier attachment with an accuracy of ~0.2 C. Shear stress versus shear rate curves were measured at 10 C intervals from high temperature (100 C) to ~ 10 C below the DSC onset of crystallization temperature. The range of shear rates ( s -1 ) was optimized for torque (lowest possible is 10 μnm) and velocity (maximum suggested of 40 rad/s). The viscosity versus temperature data were collected at constant shear rate (200 s -1 ) using the ramp procedure while the sample was cooling (1.0 C/min) from ~110 C to just above the crystallization point. Data points were collected at intervals of 1 C. The shear rate shear stress curves were fitted with the Herschel-Bulkley equation (Eq. 2.1), a model commonly used to describe the general flow behavior of liquid materials, including those characterized by a yield stress. n 0 K Eq. 2.1 Where denotes the shear stress, 0 is the yield stress below which there is no flow, K the consistency index and n the power index. n depends on constitutive properties of the material. For Newtonian fluids n = 1, shear thickening fluids, n 1 and for shear thinning fluids, n 1. The experimental viscosity temperature data were analyzed using a generalized form of the van Velzen expression (GvVE, Eq. 2.2). 53

79 1 ln A 1 m T Eq. 2.2 The GvVE yields parameters which are physically meaningful; its parameter A relates directly to the magnitude of the viscosity of the liquid and its exponent m is related to the complexity of the molecule similar to the parameters of the Andrade and generalized Andrade models [52]. The goodness of fit was determined using the percent relative deviation (RD%), referred to herein as residuals (Eq. 2.3). RD% 100 exp exp cal Eq. 2.3 Where exp and cal are the experimental and calculated viscosities, respectively. 2.3 Results and Discussion Chemical Characterization of PMTAG The acid value of PMTAG was less than 1 mg KOH/g, indicating a very low free fatty acid content. The degree of unsaturation of PMTAG as evaluated by its iodine value (IV = 52) was higher compared to the starting palm oil (IV= 45), attributed to the overall lower molecular weight of its unsaturated TAGs. Note that the IV of PMTAG is also higher than any highly saturated vegetable oil such as coconut oil (IV: 7-10) and palm kernel oil (IV: 16-19), but much lower than that of the highly unsaturated vegetable oils such as: soybean oil (IV: ), sunflower oil (IV: ), linseed oil (IV: ), olive oil (IV: 80-88), tung oil (IV: ), and grape seed oil (IV: ) [53]. 54

80 2.3.2 Compositional Analysis of PMTAG The compositional analysis of PMTAG was performed using 1 H-NMR, GC and HPLC. Because of its very low free fatty acid content, the fatty acid and TAG profiles of PMTAG were determined assuming that only TAG structures were present. PMTAG would naturally comprise all possible transformations of its unsaturated TAGs and all nontransformed saturated TAGs. The general structures of the transformed TAG can be described with a model cross metathesis reaction of 1-butene and triolein (OOO) (see Scheme 2.2). The TAG structures in PMTAG as inferred from all possible transformations based on this ideal system are shown in Scheme 2.3. The TAG profile of palm oil and corresponding modified TAG in PMTAG are presented in Table 2.1. Scheme 2.2. Metathesis reaction of triolein with 1-butene. n=0, the fatty acid is 9- denenoic acid (D), n= 2, the fatty acid is 9-dodecenoic acid (Dd), and n= 8, the fatty acid is oleic acid (O). 55

81 Scheme 2.3. Possible TAG structures composing PMTAG. n=0, 2, 8; m= 11 to 20. Table 2.1. TAG profile of palm oil and corresponding modified TAG in PMTAG. TAG Triunsaturated Biunsaturated Monounsaturated Saturated Content (wt%) OLL OLO OOO Potential PMTAG composition ODD, DDD, DDDd, DDdDd, OLL, OLO, OOO, OLD, OLDd, OOD, ODD, ODDd, ODdDd, LDD, LDDd, LDdDd, DdDdDd, and their isomers POL POL, POO, PDD, POD, PDDd, PODd, PDdDd POO and their isomers SOO SOO, SDD, SOD, SDDd, SODd, SDdDd and their isomers PLL PLL, PDD, PLD, PDDd, PLDd, PDdDd and their isomers POP POP, PDP, PDdP SOS SOS, SDS, SDdS POS POS, PDS, PDdS PLP PLP, PDP, PDdP MLP MLP, MDP, MDdP PPP PPP PPM PPM PPS PPS D: 9-decenoic acid; Dd: 9-dodecenioc acid; M, myristic acid; O, oleic acid; P, palmitic acid; L, linoleic acid; S, stearic acid. DDD: 1,2,3-triyl tris(dec-9-enoate), DDS: 3-(dec-9-enoyloxy) propane-1, 2-diyl distearate, and DSS: 3-(stearoyloxy) propane-1, 2- diyl bis(dec-9-enoate). 56

82 GC results of methylated PMTAG The fatty acid composition of PMTAG as determined by GC of methylated PMTAG is presented in Table 2.2. The GC results indicate that PMTAG was comprised of ~46 mol% unsaturated fatty acids and ~54 mol% saturated fatty acids. The decenoic acid (C10:1) and 9,12 tridecenoic acid (C13:2) are the terminal double bonded fatty acids resulting from the shortening of oleic acid and linoleic acid, respectively. Dodecenoic acid (C12:1) and 9,12-pentadecenoic acid (C15:2) are non-terminal double bonds formed by the exchange of the oleic acid and C13:2 with 1-butene, respectively. As expected, the saturated fatty acids in PMTAG matched those of the natural oil. Note that the amount of linoleic acid (C18:2) that was detected in PMTAG was very small and would not impact its properties. Table 2.2. GC results of methylated PMTAG. UFA a C10:1 C12:1 C13:2 C15:1 C15:2 C18:1 C18:2 Wt.% Mol% SFA b C12:0 C14:0 C16:0 C18:0 C20:0 C21:0 Others Wt.% Mol% a UFA: unsaturated fatty acids: decenoic acid (D, C10:1), dodecenoic acid (Dd, C12:1), 9,12 tridecenoic acid (C13:2) 9-pentadecenoic acid (C15:1), 9,12-pentadecenoic acid (C15:2), oleic acid (O, C18:1), linoleic acid (L, C18:2) b SFA: saturated fatty acids: palmitic acid (P, C16:0), Lauric acid (L, C12:0), Myristic acid (M, C14:0), stearic acid (S, C18:0), Arachidic acid (A, C20:0) 57

83 H-NMR of PMTAG The 1 H-NMR spectrum of PMTAG is shown in Figure 2.1. For clarity, the spectrum is split into two panels: 1a and 1b for the δ ppm and δ ppm chemical shift ranges, respectively. The corresponding 1 H-NMR data are provided in the Appendix (Table A1). The chemical shifts were attributed according to [54]. (a) (b) Figure H-NMR of PMTAG. (a) Chemical shift range between δ 2.5 and 0.7 ppm, (b) Chemical shift range between δ 6.0 and 4.0 ppm The -CH2CH(O)CH2- and -OCH2CHCH2O- protons of the glycerol skeleton of the TAG structure were distinctly presented at δ ppm and ppm, respectively. Two kinds of double bonds were detected: (1) terminal double bonds (n= 0 in Scheme 2.3), -CH=CH2 and CH=CH2 at δ 5.8 ppm and 5.0 to 4.9 ppm, respectively, and (2) internal double bonds (n 0 in Scheme 2.3), -CH=CH- at δ ppm. The α-h to ester group - C(=O)CH2- was presented at δ ppm, α-h to -CH=CH- was presented at δ ppm, and β-methylene proton (-C(=O)CH2CH2-) was presented at δ 1.60 ppm. Also, two kinds of CH3 were detected, one at 1.0-;0.9 ppm (n= 2 in Scheme 2.3), and another at ppm (n= 8 in Scheme 2.3). The signature peak of the proton between two double 58

84 bonds (the chemical shift at ppm) indicative of polyunsaturated fatty acids was not presented by 1 H-NMR of PMTAG. 1 H-NMR analysis confirmed that the metathesis reaction did not alter the overall saturation profile inherited from the starting palm oil but dramatically modified the configuration and structure of the unsaturated TAGs. The relative amounts of saturated fatty acids, terminal and internal double bond structures of the PMTAG, as evaluated based on the relative area under their characteristic 1 H-NMR peaks are presented in Table 2.3. Note that the terminal double bond (mol%), internal double bond RTDB (mol%) and saturated fatty acid (mol%) were calculated based on the integrated protons under 5.0 to 4.9 ppm, δ ppm and ppm respectively. These data indicate that PMTAG was constituted of approximately ~50% saturated and ~50% unsaturated fatty acids, half of which were terminal double bonds (n=0 in Scheme 2.3). The internal double bonds (n 0 in Scheme 2.3) contain trans-(δ ppm) and cis (δ ppm)-configurations with a trans-/cis- ratio of ~2:1. Table 2.3. Relative amounts of saturated and unsaturated structures in PMTAG as determined by 1 H-NMR. Fatty Acids Structure Content (mol %) Terminal double CH=CH2 bond CH=CHCH2CH=CH CH=CHCH2CH3 Unsaturated CH=CHCH2CH2CH2CH2CH3 Internal double CH=CHCH2CH2CH2CH2CH2CH2CH2CH2CH bond CH=CHCH2CH=CHCH2CH2CH2CH2CH2CH3 CH=CHCH2CH=CHCH2CH3 Saturated

85 HPLC results of PMTAG The HPLC curves of PMTAG recorded using the method described in Section are shown in Figure 2.2. The corresponding HPLC data are reported in Table 2.4. The analysis of the HPLC of PMTAG was carried out with the help of purified DDD, DDS and DSS used as reference standards, which was synthesized and characterized in our laboratory. These TAGs are representatives of tri-unsaturated, di-unsaturated and monounsaturated TAGs that result from 1-butene cross metathesis of palm oil DDD DDS LSU DSS Time (min) Figure 2.2. HPLC of PMTAG (solid line) superimposed with the HPLC of DDD, DDS and DSS. The standard TAGs are indicated at the side of their HPLC trace (dashed lines) As shown in Figure 2.2, an excellent separation of the HPLC peaks was obtained for PMTAG. Figure 2.2 shows three main groups of HPLC peaks delineated by the elution 60

86 times of DDD, DDS and DSS. This indicates the presence of three groups of molecules: (1) the triunsaturated TAGs showing before DDS, (2) TAGs with two unsaturated moieties (shortened or not) and those with shortened single unsaturated moiety showing after DDD up to DSS, and (3) the non-shortened monounsaturated and saturated TAGs showing after DSS (retention times higher than 52 min). The area % from the HPLC chromatogram of each peak is presented in Table 2.4. The individual peaks can be assigned more specifically with the help of the trend in elution time reported in the literature for TAG standards [55]. The TAGs were shown to usually elute successively from MMM (trimyristoylglycerol) to SOS (1,3-distearoyl-2-oleoyl-sn-glycerol) according to molecular weight and saturation level in the order MMM, MMP (1,2-dimyristoyl-3-palmitoyl-sn-glycerol), PPM (1,2- dipalmitoyl-3- myristoyl -sn-glycerol), OOO (Triolein), OOP (1,2-dioleoyl-3-palmitoylsn- glycerol), PPO (1,2-dipalmitoyl-3- oleoyl -sn-glycerol), PPP (tripalmitoylglycerol), OOS (1,2-dioleoyl-3-stearoyl-sn- glycerol), POS (1-palmitoy-l,2-oleoyl,3-stearoyl-snglycerol) and SOS. DDD eluted first (at ~10.4 min in Figure 2.2) because it has the lowest molecular weight and highest unsaturation. The group of HPLC peaks that are closest to DDD are attributable to the highly unsaturated and low molecular weight TAGs. DDD was followed successively by the triunsaturated TAGS, like DDDd, DDdDd, DdDdDd, DDO, DDL etc. and their isomers, at retention times between 11 and 18 min. These were followed by the diunsaturated TAGs having the formula DDX (where X=P, M) before DDS (19.9 min). The diunsaturated molecules with structures like XDDd, XDdDd, XOD, XODd (X= S, P etc.) and their isomers eluted after DDS at retention time between 20 and 32 min. DXX and DdXX type of TAG structures (X= P, M) may possibly have eluted before DSS between min. According to the succession criteria established using [55], DSS was 61

87 followed by DdSS, POS, PPS, SOS and their isomers between 51 and 80 min. The low molecular weight saturated TAG PPP and PPM may have possibly eluted between the triunsaturated and diunsaturated TAGs. Table 2.4. HPLC analysis data of PMTAG. Peak RT (min) Area (%) Structure DDD DDS DSS Physical Properties of PMTAG Thermogravimetric Analysis of PMTAG The TGA and DTG profiles of PMTAG are shown in Figure 2.3. The DTG curve presented a single peak at ~399 C indicating a one-step degradation process that is generally associated with the breakage of the ester bonds [56]. Note however that the DTG presented an asymmetrical low temperature wing that suggests that some evaporation has occurred before degradation. Such evaporation is possible due to the presence of low molecular weight molecules in the PMTAG. 62

88 100 Weight Loss (%) TGA DTG DTG /% o C Temperature ( o C) Figure 2.3: TGA and DTG profiles of the PMTAG. The temperature of degradation determined at 1%, 5% and 10% weight loss ( T 1%, T T 5% and 10%, respectively) were ~260 C, 310 C and 330 C, respectively. These values are ~20 C lower than those measured for palm oil [57], probably due to the recording of the volatilisation of the low molecular weight components of PMTAG. The onset of thermal degradation ( T on ) of PMTAG as defined by the intersection of the zero weight loss baseline with the tangent at the inflection point of the TGA curve, was at 339 C, a relatively lower temperature than the 347 C reported for palm oil [57]. However, the DTG peak temperature of PMTAG (~399 C) is relatively higher than what was recorded for palm oil (381 C) [57]. This indicates that although generally starting to degrade at lower temperature, the rate of degradation of PMTAG reaches its maximum at a higher temperature because of its modified structures Thermal transition behavior The DSC thermograms obtained during cooling and subsequent heating of PMTAG (both at 5 C/min) are presented in Figure 2.4a and 2.4b, respectively. The corresponding 63

89 characteristic temperatures (onset, T on, offset, T off, and peak temperatures, T p ) are listed in Table 2.8. The cooling thermograms presented relatively well-separated thermal events (P1, P2 and P3 in Figure 2.4a). Each exotherm is attributable to overlapping peaks due to molecules with close enough structural features to crystallize in well-defined and separated ranges of temperatures [58]. This indicates that the molecules of PMTAG form specific groups which form well-defined melting portions. The DSC heating thermogram of PMTAG was more complex than its crystallization counterpart. For example, as many as eight endotherms and two prominent exotherms (at = 19.3 and 2.9 ºC in Figure 2.4b) were observed in the heating trace of PMTAG. Despite the polymorphic transformations that occurred, one can still distinguish two group of endotherms separated at about 30 C (G1 and G2 in Figure 2.4b) that can be correlated to the two groups of exotherms observed during crystallization (G1 and G2 in Figure 2.4a) indicating two distinct PMTAG portions, one melting above room temperature and the other below room temperature. Heat Flow (Wg -1 ) (Exo up) (a) G1 G2 P1 P2 P Temperature ( o C) Heat Flow (Wg -1 ) (Endo down) (b) G1 G Temperature ( o C) Figure 2.4: (a) Crystallization thermograms of PMTAG obtained (b) corresponding heating profiles (both at 5 C/min) 64

90 The DSC profile of PMTAG bare close similarity with the profile of the natural palm oil. The low and high melting portions of PMTAG are reminiscent of the stearin and olein fractions of palm oil [59]. Therefore, comparably to palm oil and for convenience, the thermal events that appeared above room temperature (G1 in Figure 2.4a and 2.4b) are associated with a stearin-like portion of PMTAG, and the thermal events that appeared below room temperature and at sub-zero temperatures (G2 in Figure 2.4a and 2.4b) are associated with an olein-like portion of PMTAG. Obviously, the portion represented by the DSC above 30 C is constituted by the highly saturated and trans- configuration species of PMTAG, so-called stearin portion, and the portion represented by the DSC below 30 C is constituted by its highly unsaturated and short length species, so-called olein portion. The relative enthalpy of crystallization estimated for the stearin (G1) and olein (G2) portions was 25 % and 75 %, respectively, of the total enthalpy. The melting enthalpy of the stearin and olein portions represent 23% and 77% of the total enthalpy, respectively, correlating very well with what was obtained with the enthalpy of crystallization. The compositional analysis of the two portions can be attempted based on the composition of PMTAG (Section 3.2) and with the help of previous knowledge of the crystallization trends observed by DSC for natural TAGs [60]. It is commonly known that saturated TAGs crystallize at higher temperature than monounsaturated TAGs followed by diunsaturated TAG and finally triunsaturated TAGs. Symmetrical TAGs crystallize at higher temperatures than their asymmetrical counterparts. Also for a given level of saturation, crystallization temperature is higher for higher mass TAGs. The saturated TAGs like: PPP, MMP and MMM, are known to crystallize above ambient followed by the 65

91 monounsaturated TAGs such as SOS, POS and PPO, which crystallize below room temperature, typically above freezing temperature. The diunsaturated TAGs like POO, OPO, OSO and SOO crystallize at lower temperature which could be as low as ~-22 ºC in the case of POO, for example [60]. The tri-unsaturated TAGs such as OOO show a single exotherm at even much lower temperature [60]. The triunsaturated DDD and the diunsaturated DDS standards, displayed two exotherms each, at ~-40 C and ~-30 C, and at ~ -3 C, ~ -15 C, respectively, which fall in the range of temperature of the olein portion of PMTAG. The monosaturated DSS standard displayed a crystallization peak at ~ 30 C and a shoulder at ~25 C, which indicates that it belongs to the stearin fraction of PMTAG. Therefore, the exotherm observed at ~32 C (P1 in Figure 2.4a) is associated with the highly saturated/trans components of PMTAG and the peak at ~12 C (P2 in Figure 2.4a) is related to the mono-unsaturated and di-unsaturated TAGs. The peak at -11 C (P3 in Figure 2.4a) is related to the TAGs with the lowest molecular mass and the most unsaturated tri-unsaturated TAGs Flow behavior and viscosity of the PMTAG Selected shear stress versus shear rate curves recorded for PMTAG between 30 ºC and 100 ºC are shown in Figure 2.5. Fits to the Herschel-Bulkley model (Eq. 2.1) are included in the figure (dashed lines in Figure 2.5). Evident from Figure 2.5, share rate shear stress curves were linear for the whole shear rates range, except at 30 ºC where it was linear below 150 s -1 only. Application of Eq. 1 generated power index values ( n ) equal to unity and no yield stress (straight lines in Figure 2.5, R 2 > ), indicating a Newtonian behavior. The deviation from the Newtonian behavior above 150 s -1 at 30 C is due to the close proximity of this temperature to the crystallization onset of PMTAG. 66

92 Shear Stress (Pa) (a) 30 T ( o C) Shear Rate (s -1 ) Figure 2.5: Shear rate versus shear stress of the PMTAG Viscosity versus temperature curves of PMTAG are presented in Figure 2.6. The exponential behavior of these curves is typical of liquid hydrocarbons [61, 62]. The experimental data collected above 30 C, a temperature corresponding to the onset of crystallization, was fitted very well with the generalized van Velzen equation (Eq. 2.2) with residuals of less than 1% (RD% in the lower panel of Figure 2.6). Below 30 C, the RD% (Eq. 2.3) is higher than 1% and increases exponentially with decreasing temperature. This cut-off is the temperature at which the flow behavior started to depart from Newtonian to shear thickening at high shear rate (curve 30 C in Figure 2.5) because PMTAG was crystallizing. The PMTAG was probably forming liquid-crystal or gel-like states below 30 C. 67

93 Viscosity (Pa.s) (b) 1 o C/min RD /% Temperature ( o C) Figure 2.6: Viscosity versus temperature of PMTAG. Dotted lines are fit to the generalized van Velzen equation (eq.2). The lower panel represents the residuals in % (RD%) versus temperature. The viscosity of liquid PMTAG is only slightly lower than that of palm oil [63] and falls in the range of the highly unsaturated vegetable oils such as soybean oil, sunflower oil, high oleic sunflower oil, and corn oil [64]. The key elements that brought the viscosity of PMTAG closer to that of the highly unsaturated vegetable oils were chiefly the modifications to the molecular mass (molecular mass decreased) introduced by the metathesis reaction. Importantly, these levels of viscosity will allow for the handling and processing techniques and equipment in the existing various applications such as the synthesis of monomers for polymers, fuel and lubricants to be used for PMTAG Synthesis of PMTAG Polyol PMTAG Polyol was prepared from PMTAG in a two-step reaction as described in Scheme 2.4: (i) epoxidation of the PMTAG by hydrogen peroxide (H2O2) and formic acid 68

94 (HCOOH), followed by (ii) hydroxylation using HClO4 as a catalyst. The reaction progress was monitored by TLC and 1 H-NMR. The products were analyzed with HPLC and 1 H- NMR. Scheme 2.4. Synthesis of PMTAG Polyol (n=0, 2, 8; m=11 to 20) Optimization of the Synthesis of PMTAG Polyol The epoxidation reaction was performed in different media (DCM, EA, THF and without solvent) and optimised for reactants content (formic acid, and hydrogen peroxide), time and temperature of the reaction. The effort was targeted at achieving the most conversion of unsaturation sites into epoxides. The hydroxylation reactions were conducted at room temperature in THF as well as in water. The ratio of the epoxy PMTAG to HClO4 and the reaction time was varied in order to optimize the cost of the polyol. The details of the epoxidation and hydroxylation reactions are presented in Table

95 The epoxidation of PMTAG using a ratio of PMTAG: Formic acid: H2O2 of 1: 1: 1.4 was effective and complete when it was run with DCM as the solvent (E1). 1 H-NMR of the epoxidized PMTAG of this experiment is shown in Figure 2.7. There were no chemical shifts related to double bonds (at 5.8, 5.4 and 5.0 ppm) indicating their complete conversion into epoxides. The chemical shifts of internal epoxy rings were presented at δ ppm and those of terminal epoxy rings at δ ppm. The chemical shift due to the protons -CH2CH(O)CH2- and -OCH2CHCH2O- of the glycerol skeleton (at δ ppm and ppm, respectively), -C(=O)CH2- (at δ ppm), α-h to -CH=CH- (at δ ppm), and -C(=O)CH2CH2- (at δ 1.60 ppm) indicate that the TAG-like glycerol backbone structure was preserved. When epoxidation was conducted in THF (E4), or EA (E5) or without solvent (E6 and E7), the epoxidation did not complete due to partial miscibility of the reactants in these experiments. The 1 H-NMR data of the epoxy of these experiments (Figures. A1, A2 and A3 in the Appendix), specifically the relative areas of the δ 5 ppm to 4.8 ppm characteristic of the terminal double bonds indicate that more than 60% of the terminal double bonds of PMTAG were not epoxidized. Also a PMTAG Polyol by-product having a formic acid unit attached to the TAG was detected (characteristic peak at δ ~8ppm in Figures. A1 and A2) in the product of epoxidation with EA (E5) and the dry epoxidation (E6 and E7). The structure of the formylated polyols is provided in Scheme A1 in the Appendix). Note that even with DCM as the solvent, the reduction of formic acid and hydrogen peroxide concentration in E2 and E3 resulted in an incomplete epoxidation by leaving more than 40% terminal bonds. A complete conversion of unsaturation of PMTAG into the 70

96 corresponding epoxide in DCM occurred at 1/ 1/ 1.4 ratio by weight of PMTAG, HCOOH and H2O2, respectively. -OOCCH2CH2- -OOCCH2- C(O)CHCH2CH3 C(O)CH(CH2)7CH3 Figure H-NMR spectrum of epoxy PMTAG The epoxidized PMTAG obtained in E1 was deemed the most suitable to make the best polyol and chosen for the hydroxylation step because all its double bonds were converted into epoxides. The hydroxylation of epoxy E1 was carried out at room temperature in a 3:2 mixture of THF: water. The hydroxylation reaction was optimized for perchloric acid in three experiments (H1-3 in Table 2.5). As expected, the concentration of perchloric acid affected both acid value and hydroxyl number of the resulting polyol strongly. With an HClO4: PMTAG weight ratio of 1:1 (H1 in Table 2.5), the reaction yielded a polyol (Polyol H1) having a large acid value (> 50 ±5 mg KOH/g) and a relatively small OH number (120 ±5 mg KOH/g). This was a clear indication of a partial hydrolysis of the TAG esters. When the HClO4 : PMTAG weight ratio was reduced to 0.1:1 and 0.05:1 (H2 and H3, respectively, in Table 2.5), the reaction yielded polyols (Polyol H2 and H3, 71

97 respectively) with similar acid value of ~2 ±1 mg KOH/g and OH number of 155 ±5 mg KOH/g. Table 2.5. Optimization data for the synthesis of PMTAG Polyol a Step Solvent b PMTAG/Formic acid/h2o2 T ( C) Time (h) Notes E1 1/ 1/ Complete; No by-products formed E2 DCM 1/ 0.3/ Not complete; > 40% terminal E3 1/ 0.2/ 1 50 double bonds remained >1 week Epoxidation E4 THF 1/ 1/ Not complete; > 60% terminal E5 EA 1/ 1/ double bonds remained Formation of by-products Not complete, >60% terminal E double bonds remained by products formed at 100 C WO 1/ 1/ 1.4 Set temperature was 60 C then E self-heated to 100 C No double bond detected; Formic ester polyol was formed Hydroxylati on Epoxy PMTAG/HClO4 Time (h) Polyol name Acid value (mg KOH/g) OH number (mg KOH/g) H1 THF 1/ 1 20 Polyol H1 >50 ~120 H2 + 1/ Polyol H2 ~6 ~150 H3 H2O 1/ Polyol H3 ~2 ~155 a E1 7: Epoxidation experiments; H1 3: hydroxylation experiments solvent. b EA: Ethyl acetate; DCM: dichloromethane; THF: tetrahydrofuran; WO: without c Listed ratio for the starting materials is based on 30% H2O2 solution and 88% formic acid solution. Polyol of H2 presented the same NMR as Polyol of H3 The acid and OH value of these polyols were explained in light of their chemical structures as revealed by 1 H-NMR. Polyols H2 and H3 presented practically the same 1 H- 72

98 NMR (Figure 2.8a), explaining the similarity in their physical properties. In both cases, the 1 H-NMR presented the peak at δ ppm characteristic of the OH groups but not the peak of the epoxides at (δ) ppm indicating that conversion to hydroxyl groups was complete. Polyol H2 and Polyol H3 exhibited the chemical shifts of methylene at δ 5.27 ppm and ppm, and methine protons at δ ppm (Figure 2.8a) typical of TAG glycerol backbones. Furthermore, the peaks at ppm, and ppm of the methine protons presented a ratio of 1:1 indicative of the integrity of the TAG backbone and confirming that the hydrolysis of the TAG did not occur for Polyol H2 and Polyol H3. The 1 H-NMR spectrum of Polyol H1 (Figure 2.8b) presented the typical chemical shifts of the OH groups and showed the chemical shifts of the TAG structure but unlike Polyol H2 and Polyol H3 did not present the 1:1 ratio of the methine protons at ppm and ppm an evidence of partial hydrolysis. -OOCCH2- C(O)CHCH2CH3 C(O)CH(CH2)7CH3 Figure H-NMR of (a) PMTAG Polyol H1and (b) PMTAG Polyol H2 and H3 73

99 Standard synthesis procedure The most economical procedure that yielded a polyol with the lowest acid value and highest OH number, i.e., Polyol H3, was chosen as the standard method to make the polyol from PMTAG. It is heretofore simple referred to as PMTAG Polyol. Note, however, that methods of Table 2.5 may be used to custom-produce polyols that would satisfactorily meet requirements for target polyurethane products Standard epoxidation procedure Formic acid (88%; 200g) was added to a solution of PMTAG (200 g) in DCM (240 ml). The mixture was cooled to 0 C in an ice bath and hydrogen peroxide (30 %, 280 g) was added drop wise while stirring with a mechanical stirrer (500 to 600 rpm). After the addition of hydrogen peroxide, the mixture was raised to 50 C and kept at this temperature with stirring until the reaction was complete. The reaction was monitored by a combination of TLC and 1 H-NMR and was deemed complete after 48 h. The reaction mixture was then diluted with 250 ml of DCM, washed with water (200 ml 2), and then with saturated sodium hydrogen carbonate (200 ml 2), and again with water (200 ml 2). The resulting epoxy PMTAG product was rotary evaporated to remove the solvent, and then was dried over anhydrous sodium sulphate Standard hydroxylation procedure Approximately 200 g of crude epoxy PMTAG was dissolved at room temperature in a 500 ml mixture of THF/H2O (3:2) containing 14.5 g of perchloric acid. The resultant mixture was stirred at room temperature for 36 h, a time after which the reaction which was monitored by a combination of TLC and 1 H-NMR was deemed complete. The reaction mixture was poured into 240 ml water and extracted with CH2Cl2 (2 240 ml). The 74

100 organic phase was washed with water (2 240 ml), followed by 5% aqueous NaHCO3 (2 200 ml), and then with water again (2 240 ml), and then dried over Na2SO4. After removing the drying agent by filtration, the solvent was removed with a rotary evaporator and further dried by vacuum overnight, giving a light yellow grease-like solid Compositional analysis of PMTAG Polyol PMTAG Polyol was fractionated by flash chromatography using a mixture of ethyl acetate and hexanes as eluent (ratio EA: Hx from 1:6 to 1:2). Since PMTAG Polyol is a complex mixture of diols, tetrols and hexols with similar polarities, it is very difficult to separate the individual molecules with 100% purity. However, the chromatographic seperation yielded groups of polyols (fractions), which helps to explain the composition of the PMTAG Polyol. Eight (8) fractions were collected and were characterized by 1 H-NMR, MS and HPLC. The 1 H-NMR, MS and HPLC data are presented in Table 2.6. The structures of PMTAG Polyol present in the polyol fractions determined based on MS and 1 H-NMR are provided in the Appendix Scheme A H-NMR and MS Results The 1 H-NMR spectrum of Fraction 1 indicated saturated TAG structures only. It presented the chemical shift of a glycerol skeleton (at δ ppm and ppm related to -CH2CH(O)CH2- and -OCH2CHCH2O- protons, respectively) but not the peaks related to proton neighbored by hydroxyl groups (at δ ppm), or terminal (at δ 5.8 ppm, ppm) and internal double bonds (δ ppm). Fraction 2 and Fraction 3 comprised the hydrolyzed products with no TAG backbone of the PMTAG polyol. Fraction 4 (C53H102O8 H2O) and Fraction 5 (C52H100O8 2H2O) are PMTAG diols derived of oleic acid (Scheme 2.5a). Fraction 6 was a mixture of PMTAG diols derived from oleic acid and 75

101 9-dodecenoic acid of PMTAG (Scheme 2.5a and 2.5b, respectively). Fraction 7 was a mixture of PMTAG diols and tetrols derived from oleic acid, 9-dodecenoic acid and 9- decenoic acid (Scheme 2.5a, 2.5b and 2.5c, respectively). Fraction 8 was a mixture of PMTAG diols, PMTAG tetrols and PMTAG hexols derived from the diols of oleic, 9- dodecenoic and 9- decenoic acids. The relative amount of hexols, tetrols and diols with terminal hydroxyl groups in PMTAG polyol, as estimated by 1 H-NMR was ~24.1%. This value is consistent with initial terminal double bonds composing PMTAG. a) Oleic acid-like diol: b) 9-dodecenoic acid-like diol: c) 9-decenoic acid-like diol: Scheme 2.5. Diol structures produced from oleic acid, 9-dodecenoic acid and 9- decenoic acid present in the PMTAG as a result of epoxidation followed by hydroxylation. Table 2.6. Characterization of PMTAG Polyol fractions 1 H-NMR Chemical shifts a MS Formula Structure b F1 5.2 (1H, m), (2H, dd)), (2H, dd), (6H, t), (6H, m), 1.2 (69H, m), 0.8 (9H, t) C61H118O C54H104O6 Saturated TAGs F (5H, m), (4H, m), 1.6 (4H, m), 1.2 (40H, m), 0.8 (6H, t) C42H82O5 Not a TAG structure; Contains hydrolyzed byproducts 76

102 F3 5.2 (0.1H, m), (2.4H, m), 3.6 (1H, t), (3H, t), (48H, m), 0.8 (6H, t) C50H96O8 Not typical TAG structure; Contain hydrolyzed by-products with oleic acid diols F4 5.2 (1H, m), (2H, dd), (2H, dd), (2H, m), (6H, m), (78H, m), 0.8 (9H, t) C53H102O8 H2O TAG-like diols containing one oleic acid-like diol F5 5.2 (1H, m), (2, dd), (2H, dd), 3.6 (1.5H, br), 3.4 (1.1H, m), (6H, m), (77H, m), 0.8 (9H, t) C52H100O8 2H2O TAG-like diols containing one oleic acid-like diol F6 5.2 (1H, m), (2H, dd), (2H, dd), (3.2H, m), (6H, m), (64H, m), 1.0 (3H, t), 0.8 (6H, t) C55H106O C48H92O8 H2O C48H92O8 2H2O TAG-like diols containing one oleic acid-like or/and one 9-dodecenoic acid-like diols F7a F7b F7c 5.2 (1H, m), (2H, dd), (2H, dd), (3.41H, m), (6H, m), (66H, m), 1.0 (2.6H, t), 0.8 (6H, t) 5.2 (1H, m), (2H, dd), (2H, dd), (3.1H, m), (6H, m), (64H, m), 1.0 (2.7H, t), 0.8 (6H, t) 5.2 (1H, m), (2H, dd), (2H, dd), (3.3H, m), (5.8H, m), (58H, m), 1.0 (1.3H, t), 0.8 (5.2H, t) C51H98O10 TAG-like diols containing one 9-dodecenoic acid-like diol; C47H90O10 H2O; C45H86O10 2H2O; C48H92O8 2H2O C45H86O10 H2O; C48H92O8 H2O TAG-like tetrols containing one or two oleic acid-like diols or/and one 9- dodecenoic acid-like diol C45H86O10 H2O TAG-like diols containing one 9-dodecenoic acid-like diol; C47H90O C49H94O10 TAG-like tetrols containing one or two oleic acid-like diols or/and one 9-dodecenoic acidlike diol C39H74O10 H2O TAG-like diols containing one 9-decenoic acid- like C45H86O10 H2O diol; C48H92O10 H2O TAG-like tetrols containing one or two oleic acid-like, one or two 9-dodenonic acid- 77

103 like or/and one 9-decenoic acid- like diols F8 5.2 (1H, m), (2H, dd), (2H, dd), (6.2H, m), (5.6H, m), (58H, m), 1.0 (1.0H, t), 0.8 (5.1H, t) C42H80O C44H84O12; C45H86O10 H2O; C48H92O8 H2O C49H94O12 TAG-like hexols containing one or two oleic acid-like and one or two 9-dodecenoic acid-like derived diols; TAG-like tetrols containing one 9-decenoic acid- like derivatives and one oleic acid-like or 9-dodecenoic acid-like diol; C33H62O12 a 1 H-NMR Chemical shifts, δ, in CDCl3 (ppm) TAG-like diols containing one 9-decenoic acid- like diol. b Structures determined based on 1 H-NMR and MS (Scheme A2 in the Appendix) HPLC Results A good separation of PMTAG diols and tetrols was achieved with the HPLC method. However, standards were not available for all of the polyols hence, HPLC calibration curves are not available for every component of the polyols in PMTAG Polyol. Hence the composition of polyols cannot be quantified using the HPLC peaks. However the HPLC data of PMTAG Polyol and the fractions is helpful for the comparison of different polyol components in the PMTAG Polyol. The HPLC of PMTAG Polyol is shown in Figure 2.9 and the HPLC of the fractions of PMTAG Polyol are provided in the Appendix in Figure. A4. 78

104 LSU Time (min) Figure 2.9. HPLC of PMTAG Polyol. The HPLC showed single peaks for almost all the fractions indicating that a very good separation was obtained with column chromatography. The HPLC peaks of the PMTAG polyol fractions were easily assigned to the main structures, i.e., saturated TAGs, diols, tetrols, and hexols that were detected by 1 H-NMR and MS. The analysis of the HPLC of the PMTAG Polyol based on the succession of the HPLC retention times of its fractions was carried out seamlessly. The major structures present in the PMTAG polyol were quantified quite accurately using HPLC relative area with the help of the PMTAG polyol fractions used as standards. The HPLC data of the PMTAG Polyol fractions indicate that the saturated TAGs (F1) eluted first (RT between min) and the molecules with the largest number of hydroxyl groups (F8) eluted last (RT> 31 min). Note that the amount of saturated TAG structures determined from the relative area of HPLC peak of F1 (~42%) matches closely the amount of saturated material (~47%) present in the PMTAG starting material. The saturated TAGs (F1) were followed by the hydrolyzed by-products (F2 and F3) at

105 min then by the PMTAG diols (F4-F6) at 15.5 to 20.5 min. The mixture of PMTAG diols of short and long fatty chains eluted between 15 to 21 min. F7, the fraction of PMTAG comprising PMTAG tetrols with short fatty chains and PMTAG diols with internal and terminal OH groups eluted at 20.5 to 22.3 min and constituted ~ 15.9 % of the total polyol. F8 which comprised a mixture of diols, tetrols and hexols eluted last at min. HPLC area of F8 was ~29% of the total. The area under the HPLC peaks of diols, tetrols and hexols together constituted ~52% of the total. Note that the relative area of each fraction singled out from the HPLC of the PMTAG polyol matched very well the value obtained with the area of the individual HPLC of the fraction to the sum of the areas of the individual HPLC of the fractions. Table 2.7. HPLC retention time (RT, min) and relative area (A%) of column chromatography fraction of PMTAG polyol (F1-F8) obtained from the analysis of the HPLC of PMTAG Polyol Fraction RT A% F F F F F F F F

106 2.3.6 Composition of PMTAG Polyol The 1 H-NMR, MS and HPLC of PMTAG Polyol fractions revealed 42% of unreacted saturated fatty acids, 8% of PMTAG diols (with two hydroxyl groups), 16% of a mixture of PMTAG diols and tetrols (with four hydroxyl groups) and 30% of PMTAG diols, tetrols and hexols (with six hydroxyl groups). The structures detected by 1 H-NMR and MS in the PMTAG polyol fractions (F1-F8) are listed in the Appendix in Scheme A2. The general structures of PMTAG polyol are shown in Scheme 2.6. These were determined based on the above data with the help of the structures of PMTAG (see Section 3.2). These include PMTAG diols, PMTAG tetrols and PMTAG hexols, all with terminal hydroxyl groups (n= 0 in Scheme 2.6) as well as internal hydroxyl groups (n=2 or 8 in Scheme 2.6). The polyol structures with terminal hydroxyl groups were derived from 9- decenoic acid (n=0 in Scheme 2.6) and those with internal hydroxyl groups (secondary hydroxyl groups) were formed from fatty acids like 9-dodecenioc acid (n=2 in Scheme 2.6) and oleic acid (n=8 in Scheme 2.6). 81

107 Scheme 2.6. General structures present in PMTAG Polyol (n= 0, 2, 8; m=11 to 20) Physical Properties of PMTAG Polyol Thermal degradation of PMTAG Polyol The TGA and DTG curves of PMTAG Polyol are presented in Figure The onset temperature of degradation determined at different early weight loss values ( T 1% ~ 215 C, T 5% ~295 C and T 10% ~320 C at 1%, 5% and 10%, respectively) were lower by ~ 15 C than those of PMTAG due to the loss of the terminal hydroxyl groups which occur before the breakage of the ester bonds. The main DTG peak at 374 C (arrow 1 in Figure 2.10) is associated with the loss of fatty acid chains resulting from the breakage of the ester bonds [56, 65]. The small DTG shoulder peak at ~ 450 C (arrow 2 in Figure 2.10) indicate a second step of degradation wherein the decomposition of ester groups and others high 82

108 decomposition temperature fragments and the degradation of the remaining carbonaceous materials from the previous step were recorded [66] Weight Loss (%) DTG (% o C -1 ) Temperature ( o C) Figure 2.10: TGA and DTG profiles of PMTAG Polyol Crystallization and Melting Behavior of PMTAG polyol The DSC thermograms obtained during cooling and subsequent heating of PMTAG Polyol are presented in Figure 2.11a and 2.11b, respectively. The corresponding characteristic temperatures ( T on : onset, T off : offset, and T p : peak temperatures) are listed in Table 2.8. The DSC of PMTAG Polyol resemble that of PMTAG in many aspects. The cooling trace of PMTAG Polyol presented two well-defined exotherms (P1 and P2 in Figure 2.11a). Although not as separated as in PMTAG, P1 and P2 indicate a high and a low crystallizing portions reminiscent of the stearin- and olein-like portions of PMTAG. The heating thermogram of PMTAG Polyol displayed also two distinct groups of endothermic events (G1 and G2 in Figure 2.11b) that are associated with the melting of the stearin- and olein-like portions of PMTAG Polyol. 83

109 0.8 (a) P1 0.0 (b) Heat Flow (Wg -1 ) (Exo up) P2 Heat Flow (Wg -1 ) (Endo down) o C G Temperature ( o C) -0.5 G Temperature ( o C) polyol. Figure 2.11: (a) Crystallization of PMTAG polyol (b) heating profile of PMTAG The crystallization and melting peaks of the stearin-like portion of the polyol occurred at the positions of those of the PMTAG saturated moieties. For example, P1 of the polyol (Figure 2.11a) and P1 of PMTAG (Figure 2.4a) presented similar T on (~25.5 C and~24.5 C, respectively) and T p (~24 C and ~23 C, respectively). This portion of PMTAG Polyol was constituted primarily of the non-functional TAG structures that were not altered by the epoxidation and hydroxylation reactions. The low temperature exothermic event P2 of the olein-like portion of PMTAG Polyol peaked at a relatively higher temperature than the P2 of PMTAG (~14 C compared to 4 C, Table 2.8) because of the added OH groups. The presence of the hydroxyl groups explain also the higher melting peaks of the polyol (in 84

110 Table 2.8, T 3 = 30 C for PMTAG Polyol and 25 C for PMTAG). Note that the enthalpy of crystallization measured for P1 of the polyol was 40 J/g, i.e., 42 % of the total enthalpy of crystallization of the polyol, reflects the balance between the hydroxyl derivatives and the saturated components of PMTAG Polyol. Table 2.8. Thermal data of the PMTAG and PMTAG Polyol obtained on cooling and heating (5 C/min). T on, T off, andt p, p= 1-6: onset, offset, and peak temperatures, H CM, : Enthalpy, C: crystallization and M: melting. Temperature ( C) Cooling T 1 T 2 T 3 T 4 T 5 T 6 T on Enthalpy (J/g) H T off H1 H C 2 PMTAG Polyol G2 G1 Heating T 1 T 2 T 3 T 4 T 5 T 6 T on T H M off PMTAG Polyol The crystallization and melting data indicate that PMTAG polyol can be separated into a saturated-rich solid fraction (P1) and a hydroxyl-rich liquid-like fraction (P2). However, even if a good separation was obtained, the low melting temperature fraction of PMTAG Polyol would not remain liquid at room temperature and would solidify in time because of the close proximity and overlap of its crystallization trace with that of the high melting temperature fraction. With controlled fractionation protocols, the amount of hydroxyl groups in each fraction may be controlled to some extent, giving custom-made 85

111 functionalized materials for use in applications that can range from cosmetics to waxes and high-end polymers Flow and Viscosity Behavior of PMTAG polyol The study of the rheological properties of polyols are very important for the optimization of their processing and transformation. Selected shear stress versus shear rate curves recorded for PMTAG Polyol between 40 ºC to 100 ºC are shown in Figure Fits to the Herschel-Bulkley model (Eq. 2.1) are included in the figure (dashed lines in Figure 2.12). Evident from Fig. 6, share rate shear stress curves were linear for the whole shear rates range, except at 40 ºC where it was linear below 650 s -1 only. Application of Eq. 2.1 to the linear region of the share rate shear stress data generated power index values ( n ) all practically equal to unity and no yield stress (straight Lines in Figure 2.12, R 2 > ), indicating a Newtonian behavior. The deviation from the Newtonian behavior above 650 s -1 at 40 C is due to the close proximity of this temperature to the crystallization onset of the material. Shear Stress (Pa) (a) C) Shear Rate (s -1 ) Figure 2.12: Shear rate versus shear stress of PMTAG Polyol 86

112 0.8 Viscosity (Pa.s) RD % Temperture ( o C) Figure 2.13: Viscosity versus temperature measured while cooling PMTAG Polyol at ( ) 1 C/min. Dotted lines represent the calculated viscosity using the generalized van Velzen equation (Eq.2.2). Lower panel represent the residuals in % (RD%) versus temperature. The cut-off is indicated with a vertical dashed line. The viscosity versus temperature curve of PMTAG polyol shown in Figure 2.13 presented the typical exponential behavior of liquid hydrocarbons [62, 67]. The fit of the experimental data to the generalized van Velzen equation (GvVE, Eq. 2.2) was excellent in the temperature region where PMTAG Polyol was liquid and deviates sharply below 35 C (cut off line in the lower panel of Figure 2.13). The deviation as represented by the residuals (RD%) is higher than 1% and increases significantly with decreasing temperature. The cut-off is consistent with the temperature at which shear stress versus shear rate data showed a shear thickening limit to the Newtonian behavior of the polyol at high shear rate (curve obtained at 40 C in Figure 2.12). The sharp increase of RD% (Eq. 2.3) is understandable because after the cut-off temperature, which is very close to the onset of 87

113 crystallization ( T on ) of the material, liquid-crystal or gel-like states of PMTAG polyol nucleate and grow very rapidly increasing dramatically the viscosity. The viscosity of PMTAG polyol was higher than PMTAG at all temperatures due to the hydroxyl groups which increase the polarity and intermolecular attractive force between the molecules by hydrogen bonding [68]. The viscosity values of some of the polyols from highly unsaturated oils that are used for polyurethane applications are; soy polyol (by ozonolysis): 680 mpa.s at 25 C, canola polyol (by ozonolysis): mpa.s at 25 C, rapeseed oil polyol (epoxidation/hydroxylation): 140 at 40 C and soy polyol (epoxidation/hydroxylation): at 70 C respectively[13, 14, 69, 70]. Although the viscosity PMTAG Polyol at 40 C (330 mpa.s) doesn t exactly match these values, it is close enough and in the range of the feasibility of using the same methodologies to make polyurethanes without drastic changes to the existing handling and processing techniques. 2.4 Conclusions 1-butene metathesized palm oil (PMTAG) is revealed to be different from the natural oil in terms of composition, chemical structure and physical properties. The metathesis reaction preserved the saturation level of ~50% of the natural oil and yielded 24.9 mol% of fatty acids with terminal double bonds. The DSC thermal analysis revealed that PMTAG, although with a significantly different composition, was constituted of a highmelting and a low-melting portions akin to the well-known stearin and olein fractions of palm oil. It is therefore possible to fractionate PMTAG using standard methods to obtain feedstock with desired unsaturation levels. Furthermore, its flow behavior and viscosity profile, which is similar to common highly unsaturated vegetable TAG oils, makes it 88

114 suitable to be processed and transformed into more valuable materials by existing technology. Fully functionalized polyols were successfully produced from PMTAG by standard epoxidation and hydroxylation. The PMTAG polyol with a relatively high hydroxyl value (155 mg KOH/g) and primary diols, tetrols and hexols and internal hydroxyl groups which match the PMTAG double bond configuration map, is a suitable starter for a variety of applications not possible with a non-transformed TAG oil, including rigid and flexible polyurethane foams. Also inherited from PMTAG, PMTAG Polyol presented a high melting and low melting molecular fractions that can be directly related to the stearin-like and olein-like fractions of PMTAG. With adequate melting temperature and viscosity profile, also in the range of those of polyols made from unsaturated vegetable oil, PMTAG polyol would lend itself to easy processing and transformation. The cross-metathesis reaction transformed the natural palm oil into a more useful material with structural and physical characteristics that improved its prospects as a substrate for further transformation and the manufacture of a variety of materials including waxes, cosmetics and polyurethanes. Acknowledgements We would like to thank the Grain Farmers of Ontario, Elevance Renewable Sciences, Trent University, the GPA-EDC, Ontario Ministry of Agriculture, Food and Rural Affairs, Industry Canada and NSERC for financial support. 89

115 2.5 References [1] Lligadas G, Ronda JC, Galia M, Cádiz V. Plant oils as platform chemicals for polyurethane synthesis: current state-of-the-art. Biomacromolecules. 2010;11(11): [2] Biermann U, Friedt W, Lang S, Lühs W, Machmüller G, Metzger JO, et al. New syntheses with oils and fats as renewable raw materials for the chemical industry. Angewandte Chemie International Edition. 2000;39(13): [3] Desroches M, Escouvois M, Auvergne R, Caillol S, Boutevin B. From vegetable oils to polyurethanes: synthetic routes to polyols and main industrial products. Polymer Reviews. 2012;52(1): [4] Petrović ZS. Polyurethanes from vegetable oils. Polymer Reviews. 2008;48(1): [5] Gunstone F. Vegetable oils in food technology: composition, properties and uses: John Wiley & Sons, [6] Firm MRCaC. Polymer Foam Market By Types (Polyurethane, Polystyrene, Polyvinyl Chloride, Polyolefin, Phenolic, Melamine and Others), Applications (Packaging, Building & Construction, Furniture & Bedding, Automotive, Wind Energy and Others) & Geography - Global Trends & Forecasts to marketsandmarkets. 2013;CH [7] Zhang L, Jeon HK, Malsam J, Herrington R, Macosko CW. Substituting soybean oilbased polyol into polyurethane flexible foams. Polymer. 2007;48(22): [8] Tan S, Abraham T, Ference D, Macosko CW. Rigid polyurethane foams from a soybean oil-based polyol. Polymer. 2011;52(13): [9] Khoe TH, Otey FH, Frankel EN. Rigid urethane foams from hydroxymethylated linseed oil and polyol esters. Journal of the American Oil Chemists' Society. 1972;49(11): [10] Hu YH, Gao Y, Wang DN, Hu CP, Zu S, Vanoverloop L, et al. Rigid polyurethane foam prepared from a rape seed oil based polyol. Journal of applied polymer science. 2002;84(3): [11] Chuayjuljit S, Sangpakdee T, Saravari O. Processing and properties of palm oil-based rigid polyurethane foam. The Journal of The Minerals, Metals & Materials Society. 2007;17:7-23. [12] Babb DA. Polyurethanes from renewable resources. Synthetic Biodegradable Polymers: Springer; p [13] Petrović ZS, Zhang W, Javni I. Structure and Properties of Polyurethanes Prepared from Triglyceride Polyols by Ozonolysis. Biomacromolecules. 2005;6(2):

116 [14] Narine S, Kong X, Bouzidi L, Sporns P. Physical Properties of Polyurethanes Produced from Polyols from Seed Oils: I. Elastomers. Journal of the American Oil Chemists' Society. 2007;84(1): [15] Guo A, Demydov D, Zhang W, Petrovic ZS. Polyols and Polyurethanes from Hydroformylation of Soybean Oil. Journal of Polymers and the Environment. 2002;10(1): [16] Dai H, Yang L, Lin B, Wang C, Shi G. Synthesis and characterization of the different soy-based polyols by ring opening of epoxidized soybean oil with methanol, 1, 2- ethanediol and 1, 2-propanediol. Journal of the American Oil Chemists' Society. 2009;86(3): [17] Pawlik H, Prociak A, Pielichowski J. Synteza polioli z oleju palmowego przeznaczonych do otrzymywania elastycznych pianek poliuretanowych. Czasopismo Techniczne Chemia. 2009;106: [18] Hou CT, Lin J-T. Methods for microbial screening and production of polyol oils from soybean oil through bioprocess. Biocatalysis and Agricultural Biotechnology. 2013;2(1):1-6. [19] Guo A, Zhang W, Petrovic ZS. Structure-property relationships in polyurethanes derived from soybean oil. Journal of Materials Science. 2006;41(15): [20] Zlatanić A, Petrović ZS, Dušek K. Structure and Properties of Triolein-Based Polyurethane Networks. Biomacromolecules. 2002;3(5): [21] Nagendran B, Unnithan U, Choo Y, Sundram K. Characteristics of red palm oil, a carotene-and vitamin E rich refined oil for food uses. Food & Nutrition Bulletin. 2000;21(2): [22] Lida H, Sundram K, Siew WL, Aminah A, Mamot S. TAG composition and solid fat content of palm oil, sunflower oil, and palm kernel olein blends before and after chemical interesterification. Journal of the American Oil Chemists Society. 2002;79(11): [23] Edem D. Palm oil: Biochemical, physiological, nutritional, hematological and toxicological aspects: A review. Plant Foods for Human Nutrition. 2002;57(3-4): [24] Santosa SJ. Palm oil boom in Indonesia: from plantation to downstream products and biodiesel. CLEAN Soil, Air, Water. 2008;36(5 6): [25] Ong A, Goh S. Palm oil: a healthful and cost-effective dietary component. Food & Nutrition Bulletin. 2002;23(1): [26] Tanaka R, Hirose S, Hatakeyama H. Preparation and characterization of polyurethane foams using a palm oil-based polyol. Bioresource technology. 2008;99(9):

117 [27] Ogoshi T, Miyawaki Y. Soap and related products: Palm and lauric oil. Journal of the American Oil Chemists Society. 1985;62(2): [28] Chang T-S, Yunus R, Rashid U, Choong TS, Awang Biak DR, Syam AM. Palm Oil Derived Trimethylolpropane Triesters Synthetic Lubricants and Usage in Industrial Metalworking Fluid. Journal of oleo science. 2015(0). [29] Shomchoam B, Yoosuk B. Eco-friendly lubricant by partial hydrogenation of palm oil over Pd/γ-Al 2 O 3 catalyst. Industrial crops and products. 2014;62: [30] Abu-Hamdeh NH, Alnefaie KA. A comparative study of almond and palm oils as two bio-diesel fuels for diesel engine in terms of emissions and performance. Fuel. 2015;150: [31] Tulathammakit H, Kitiyanan B. Synthesis of Methyl Ester Sulphonate Surfactant from Palm Oil Methyl Ester by Using UV or Ozone as an Initiator. Chemical Engineering. 2014;39. [32] Lee C, Ooi T, Chuah C, Ahmad S. Rigid polyurethane foam production from palm oil-based epoxidized diethanolamides. Journal of the American Oil Chemists' Society. 2007;84(12): [33] Pawlik H, Prociak A. Influence of palm oil-based polyol on the properties of flexible polyurethane foams. Journal of Polymers and the Environment. 2012;20(2): [34] Arniza M, Hoong S, Idris Z, Yeong S, Hassan H, Din A, et al. Synthesis of Transesterified Palm Olein-Based Polyol and Rigid Polyurethanes from this Polyol. Journal of the American Oil Chemists' Society. 2015;92(2): [35] Rybak A, Fokou PA, Meier MAR. Metathesis as a versatile tool in oleochemistry. European Journal of Lipid Science and Technology. 2008;110(9): [36] Mol JC, Buffon R. Metathesis in oleochemistry. Journal of the Brazilian Chemical Society. 1998;9(1):1-11. [37] Thomas RM, Keitz BK, Champagne TM, Grubbs RH. Highly selective ruthenium metathesis catalysts for ethenolysis. Journal of the American Chemical Society. 2011;133(19): [38] Malacea R, Dixneuf PH. Alkene Metathesis and Renewable Materials: Selective Transformations of Plant Oils. Green Metathesis Chemistry: Springer; p [39] Connon SJ, Blechert S. Recent developments in olefin cross metathesis. Angewandte Chemie International Edition. 2003;42(17): [40] Refvik M, Larock R. The chemistry of metathesized soybean oil. Journal of the American Oil Chemists' Society. 1999;76(1):

118 [41] Zlatanic A, Petrovic ZS, Dušek K. Structure and properties of triolein-based polyurethane networks. Biomacromolecules. 2002;3(5): [42] Rosenburg DW. To produce reduced chain length esters and alpha-olefins. Google Patents; [43] Li SJ, Hojabri L, Narine SS. Controlling Product Composition of Metathesized Triolein by Reaction Concentrations. Journal of the American Oil Chemists' Society. 2012;89(11): [44] Tian QP, Larock RC. Model studies and the ADMET polymerization of soybean oil. Journal of the American Oil Chemists' Society. 2002;79(5): [45] Biermann U, Metzger JO, Meier MAR. Acyclic Triene Metathesis Oligo- and Polymerization of High Oleic Sun Flower Oil. Macromolecular Chemistry and Physics. 2010;211(8): [46] Mol J. Catalytic metathesis of unsaturated fatty acid esters and oils. Topics in Catalysis. 2004;27(1-4): [47] Ahmad F, Hamdan S, Yarmo M, Alimunir A. Co-metathesis reaction of crude palm oil and ethene. Journal of the American Oil Chemists Society. 1995;72(6): [48] Patel J, Mujcinovic S, Jackson WR, Robinson AJ, Serelis AK, Such C. High conversion and productive catalyst turnovers in cross-metathesis reactions of natural oils with 2-butene. Green Chemistry. 2006;8(5): [49] RoyáJackson W. Cross-metathesis of unsaturated natural oils with 2-butene. High conversion and productive catalyst turnovers. Chemical communications. 2005(44): [50] Schrodi Y, Pederson RL, Kaido H, Tupy MJ. Synthesis of terminal alkenes from internal alkenes via olefin metathesis. Google Patents; [51] Adhvaryu A, Liu Z, Erhan S. Synthesis of novel alkoxylated triacylglycerols and their lubricant base oil properties. Industrial crops and products. 2005;21(1): [52] Harris KR. Temperature and Pressure Dependence of the Viscosities of 2-Ethylhexyl Benzoate, Bis(2-ethylhexyl) Phthalate, 2,6,10,15,19,23-Hexamethyltetracosane (Squalane), and Diisodecyl Phthalate. Journal of Chemical and Engineering Data. 2009;54(9): [53] Thomas A. Fats and fatty oils. Ullmann's Encyclopedia of Industrial Chemistry [54] Knothe G, Kenar JA. Determination of the fatty acid profile by 1H NMR spectroscopy. European journal of lipid science and technology. 2004;106(2):

119 [55] Haryati T, Man YC, Ghazali H, Asbi B, Buana L. Determination of iodine value of palm oil based on triglyceride composition. Journal of the American Oil Chemists' Society. 1998;75(7): [56] Gryglewicz S, Piechocki W, Gryglewicz G. Preparation of polyol esters based on vegetable and animal fats. Bioresource technology. 2003;87(1):35-9. [57] Wan Nik W, Ani FN, Masjuki H. Thermal stability evaluation of palm oil as energy transport media. Energy Conversion and Management. 2005;46(13): [58] Tan C, Man YC. Differential scanning calorimetric analysis of palm oil, palm oil based products and coconut oil: effects of scanning rate variation. Food Chemistry. 2002;76(1): [59] Zaliha O, Chong C, Cheow C, Norizzah A, Kellens M. Crystallization properties of palm oil by dry fractionation. Food Chemistry. 2004;86(2): [60] Man YC, Haryati T, Ghazali H, Asbi B. Composition and thermal profile of crude palm oil and its products. Journal of the American Oil Chemists' Society. 1999;76(2): [61] Eiteman M, Goodrum J. Density and viscosity of low-molecular weight triglycerides and their mixtures. Journal of the American Oil Chemists Society. 1994;71(11): [62] Goodrum JW, Eiteman MA. Physical properties of low molecular weight triglycerides for the development of bio-diesel fuel models. Bioresource technology. 1996;56(1): [63] Tangsathitkulchai C, Sittichaitaweekul Y, Tangsathitkulchai M. Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil. Journal of the American Oil Chemists' Society. 2004;81(4): [64] Santos JCO, Santos IMG, Souza AG. Effect of heating and cooling on rheological parameters of edible vegetable oils. Journal of food Engineering. 2005;67(4): [65] Chang C-C, Wan S-W. China's motor fuels from tung oil. Industrial & Engineering Chemistry. 1947;39(12): [66] Lin B, Yang L, Dai H, Hou Q, Zhang L. Thermal analysis of soybean oil based polyols. Journal of thermal analysis and calorimetry. 2009;95(3): [67] Eiteman MA, Goodrum JW. Density and viscosity of low-molecular weight triglycerides and their mixtures. Journal of the American Oil Chemists Society. 1994;71(11): [68] Li Y, Sun XS. Di-hydroxylated soybean oil polyols with varied hydroxyl values and their influence on UV-curable pressure-sensitive adhesives. Journal of the American Oil Chemists' Society. 2014;91(8):

120 [69] Kairytė A, Vėjelis S. Evaluation of forming mixture composition impact on properties of water blown rigid polyurethane (PUR) foam from rapeseed oil polyol. Industrial crops and products. 2015;66: [70] Guo A, Cho Y, Petrović ZS. Structure and properties of halogenated and nonhalogenated soy based polyols. Journal of Polymer Science Part A: Polymer Chemistry. 2000;38(21):

121 3 Water-Blown Bio-Based Rigid and Flexible Polyurethane Foams from 1-Butene Metathesized Palm oil Polyol Introduction Polyurethanes (PUs) are macromolecules containing urethane linkages (-NH-CO-O- ) that are either formed based on the reaction of isocyanate groups and hydroxyl groups [1], or via non-isocyanate pathways, such as the reaction of cyclic carbonates with amines [2], self-polycondensation of hydroxyl-acyl azides or melt transurethane methods [3]. Judicious selection of reactants enables the production of a wide range of polyurethane products such as polyurethane elastomers [4], sheets [4], adhesives [5], coatings [6], and foams [7] etc. PU foams are light weight, have good insulation properties, excellent strength to weight ratio, and impressive sound absorbing properties [1]. Furthermore, their physical properties can be tailored to a large extent by varying the structure and composition of the reacting monomers, amount of catalyst and other additives like glycerin, water etc., as well as the reaction conditions used in the foam formulation [8]. In the case of water blown polyurethane foams, the reaction of water and isocyanate produces carbon dioxide gas 1 A version of this Chapter is filed as a US provisional patent: U.S. Provisional Patent Application # , (filed August, 2013), Metathesized Triacylglycerol Palm Polyols for Use in Polyurethane Applications and Their Related Physical Properties, S.S. Narine, Prasanth. K. S. Pillai, S.Li, L.Bouzidi and A.Mahdevari and Submitted for a publication in Industrial Crops and Products. 96

122 which forms into small air bubbles. The diffusion of further carbon dioxide inflates the air bubbles leading to a well-defined cell structure [9]. PU foams are classified as rigid or flexible according to compressive strength value, and other parameters such cross link density and hydroxyl value (OH value) of the starting polyol [1]. The market for PU foams is very large and growing due to high demand across a wide range of industries such as automotive, building and construction, and packaging [10, 11]. The worth of the global polyurethane foams market was $46.8 billion in 2014 and is estimated to reach $72.2 billion by 2020 [12]. Traditionally, PU foams are prepared by the reaction of diisocyanates or polyisocyanates with petroleum-derived polyols [1]. The development of polyurethanes from renewable and environmentally friendly feedstock has become the subject of increasing research because of sustainability and other environmental concerns [13]. Vegetable oils are a particularly promising alternative feedstock for the synthesis of polyols and polyurethanes because they are biodegradable, available in large quantities, and are relatively low-cost [14]. A significant body of literature reporting on the synthesis of polyols and polyurethanes from natural oils is readily available (see for example PU foams from soybean oil [15, 16], safflower oil, corn oil, sunflower seed oil, linseed oil [17], rapeseed oil [18], and cotton seed oil [19]). Palm oil is one of the cheapest and most produced oils in the world that is touted as a viable renewable feedstock for the economical industrial production of polyols and polyurethanes [20-23]. However, palm oil does not lend itself easily to chemical modification because of its relatively high level of saturation (50% fatty acids) which caps the levels at which it can be functionalized and hence the hydroxyl value of its polyols as 97

123 compared to highly unsaturated TAG oils such as soybean oil [24]. Furthermore, similar to most other natural oils, its double bonds are internal and dispersed in the 95% triacylglycerols (TAGs) and 5% diacylglycerols (DAGs) composing the oil [24-26] which result in polyols with secondary hydroxyl groups and dangling chains. Such polyols are less reactive towards polymerization, and known to lead to incomplete crosslinking and imperfections in the polymer network [7, 27]. The regions where dangling chains are present do not support stress when the sample is loaded, and act as plasticizers that reduce the rigidity of the polymer [27, 28]. In fact, the hydroxyl value and the position of the hydroxyl groups in the fatty chain, the molecular weight of the polyol and the presence of dangling chains, are the most important factors which affect the properties of polyurethanes [27-29]. Current research efforts revolve around finding the transformation routes that would increase the potential of the natural oils as viable sources for polyols and PU foam products. Such efforts include improving existing synthesis routes, developing new chemistries and optimizing processing conditions. Olefin metathesis is an example of such novel approaches that our research group is using as a platform for improved and more suitable feedstock for the formulation of bio-based materials, particularly polyols and PUs. The foams of the present work were formulated with a polyol obtained from a product of the cross-metathesis of 1-butene and palm oil (PMTAG) (so-called PMTAG Polyol). The chemical and physical properties of the modified TAG material (PMTAG) and its polyol have already been reported [30]. 98

124 Scheme 3.1. Cross linked polyurethane foam from MDI and PMTAG Polyols. Hexol is used as a model polyol structure. PMTAG Polyol is a relatively low molecular weight material comprising ~52% of functional hexols, tetrols and diols, with half of the hydroxyl groups in terminal positions [30]. The structures of the polyol with terminal hydroxyl groups were derived from 9- decenoic acid and those with internal hydroxyl groups (secondary hydroxyl groups) were 99

125 formed from fatty acids like 9-dodecenioc acid and oleic acid[30]. The unique structure and composition of PMTAG Polyol and related thermal and rheological properties indicated enhanced reactivity and kinetics that bode well for further transformation of the material at manageable reaction conditions into starters and materials for various polymer applications such as polyurethane foams. The polymerization of PMTAG Polyol into PU foams as exemplified by a model hexol structure is shown in Scheme 3.1. The present contribution reports on the preparation and characterization of rigid and flexible foams from PMTAG Polyol. The effect of terminal hydroxyl PMTAG Polyols on the physical properties of the polyurethane foams is particularly highlighted. Rigid foams with densities ranging from 93 kgm -3 to 250 kgm -3, and flexible foams with densities ranging from 106 kgm -3 to 193 kgm -3 were prepared and characterized by FTIR to confirm the urethane linkage. The morphology of the foams was examined with scanning electron microscopy (SEM). Their thermal decomposition and thermal transition behaviours were determined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The compressive strength of the rigid and the flexible foams were determined with a texture analyzer. 3.2 Materials and Methods Materials PMTAG Polyol [30] was synthesized in our laboratory from PMTAG, a butene cross-metathesized palm oil product provided by Elevance Renewable Sciences (ERS, Bolingbrook, Il). Dibutin Dilaurate (DBTDL) and glycerin (99.5 %) were purchased from Sigma-Aldrich, Canada, and perchloride acid (70%) from Fisher Scientific, Canada. N, N- 100

126 Dimethylethanolamine (DMEA) from Fischer chemical (USA), diphenylmethane diisocynate (MDI) from Baer Materials Science (Pittsburgh, PA), and polyether-modified surfactant (TEGOSTAB B-8404) from Goldschmidt Chemical Canada Polymerization Method The amount of each component of the polymerization mixture was based on 100 parts by weight of total polyol. All the ingredients, except MDI, were weighed into a beaker and then MDI was added to the beaker using a syringe. The ingredients were then mechanically mixed vigorously for 8 to 20 s and then poured into a cylindrical Teflon mold (60 mm diameter and 35 mm long), which was previously greased with silicone release agent. The mold was sealed with a hand tightened clamp. The sample was cured for four (4) days at 45 C and post cured for one (1) day at room temperature. Rigid and flexible foams of different densities were prepared using the same polymerization protocol and formulation recipe. During the polymerization step, the amounts of mixture was controlled to achieve the desired densities Chemistry and Physical characterization techniques Fourier Transform Infrared Spectroscopy (FTIR) FTIR spectra were obtained with a Thermo Scientific Nicolet 380 FT-IR spectrometer (Thermo Electron Scientific Instruments, LLC, USA) equipped with a PIKE MIRacle TM attenuated total reflectance (ATR) system (PIKE Technologies, Madison, WI, USA.). Solid samples were loaded onto the ATR crystal area, and sample spectra were acquired over a scanning range of cm -1 for 32 repeated scans at a spectral resolution of 4 cm

127 Thermogravimetric analysis (TGA) The thermogravimetric analysis (TGA) was carried out on a TGA Q500 (TA Instruments, DE, USA) equipped with a TGA heat exchanger (P/N ). Approximately mg of sample was loaded onto the open TGA platinum pan. The sample was heated from 25 to 600 C under dry nitrogen at a constant rate of 10 C/min Differential Scanning Calorimetry (DSC) The thermal transition behavior of the PMTAG Polyol foams was investigated using a Q200 model (TA Instruments, New Castle, DE) by modulated DSC following ASTM E standard. The sample ( mg) in hermetically sealed aluminum DSC pan was first equilibrated at 25 C and heated to 150 C at 10 C/min (first heating cycle). The sample was held at that temperature for 10 min and then cooled down to -90 C at 10 C/min, and subsequently reheated to 150 C at the same rate (second heating cycle). Modulation amplitude and period were ±1 C and 60 s, respectively. The TA Universal Analysis software was used to analyze the TGA and DSC thermograms. The characteristics of non-resolved peaks were obtained using the first and second derivatives of the differential thermogravimetry (DTG) and differential heat flow Texture Analysis - Compressive Strength The compressive strength of the foams were measured at room temperature using a texture analyser (TA-TX HD, Texture Technologies Corp, NJ, USA). Samples were prepared in cylindrical Teflon molds of 60-mm diameter and 36-mm long. The cross head speed was 3.54 mm/min with a load cell of 750 Kgf. The load was applied until the foam was compressed to approximately 15% and 65% of the original thickness of the rigid and 102

128 flexible foams, respectively. The compressive strength of the rigid and flexible foams were calculated at "10% deformation" method according to the standard (literature used as reference). The flexible foams were compressed to the maximum extent (65%) of its original thickness. In the case of Rigid Foams, the compressive strength is the stress prevailing at 10% strain [31] Also compressive strength at 6% deformation of rigid foam and 25% for flexible foams are reported for comparison purpose Scanning Electron Microscopy (SEM) A scanning electron microscope (SEM, model Tescan Vega II), was used under standard operating conditions (10 kev beam) to examine the pore structure of the foams. Each sample (~2 cm 2 cm and 0.5 cm thick), cut from the centre of foam samples prepared in cylindrical Teflon molds of 60-mm diameter and 36-mm long, was coated with a thin layer of carbon (~30 nm thick) to ensure electrical conductivity in the SEM chamber and prevent the buildup of electrons on its surface. All images were acquired using a secondary electron detector to show the surface features of the samples Preparation of PU rigid and flexible foams Rigid and flexible polyurethane foams were prepared from PMTAG polyol and MDI using a previously published method [7]. The formulation recipes used to prepare the rigid and flexible foams are presented in Table 3.1. The amount of each component was based on 100 parts by weight of total polyol. The characteristics of the PMTAG Polyol (OH value and acid value) and of the diphenylmethane diisocyanate (MDI) are provided in Table 3.2. The amount of MDI which was used for the polymerization of both the rigid and flexible foams was determined in order to achieve an isocyanate index of 1.2 (NCO to OH ratio of 1.2 to 1). 103

129 The rigid foams were prepared based on a total hydroxyl value of 450 mg KOH/g. In this case, glycerine (16 parts), a poly hydroxyl cross linker, was added into the reaction mixture in order to obtain the targeted hydroxyl value (see Table 3.1). DBTDL and DMEA are the two catalysts that were used for the foam preparation. DBTDL is a cross linking catalyst which favours the gelling reaction, and DMEA, the co-catalyst, functions as a blowing catalyst during the polymerization process [1, 32]. The catalyst ratios were fixed to 1 part of the total weight of the polymerization mixture in the formulation of the rigid foams. The choice of DBTDL and DMEA and fixed ratio was based on the fairly good compressive strength previously obtained for rigid PUR foams prepared from terminal hydroxyl polyols [7]. The flexible foams were prepared based on a total hydroxyl value of 155 mg KOH/g. In this case, the catalyst amount was fixed to 0.1 parts in order to produce the most flexible foams with least compressive strength [33]. Note that no glycerine was added in the flexible foam formulation. Table 3.1. Formulation Recipe for Rigid and Flexible PMTAG Polyol Foam Ingredients Parts by weight Rigid Foam Flexible Foam PMTAG polyol OH: NCO ratio 1:1.2 1:1.2 Glycerol 16 0 Water 2 2 Surfactant 2 2 Catalyst Co-catalyst

130 Table 3.2. Composition and properties of PMTAG Polyol and diphenylmethane diisocyanate (MDI) PMTAG Polyol a MDI b Description: Light yellow waxy solid Description: Dark brown liquid Composition: Diols, tetrols and hexols: 52% Terminal hydroxyl polyol: 24% Internal hydroxyl polyol: 28% Composition: Polymeric MDI: 40-50% (4, 4 Diphenylmethane Diisocyanate): 30-40% MDI mixed isomers: 15-25% Melting Point ( C) 48 Boiling Point ( C) 208 OH Value (mg KOH/g) 155 NCO (wt%) 31.5 Acid value (mg KOH/g) 2 Functionality 2.4 Equivalent weight (g/mol) 362 Equivalent weight (g/mol) C (mpa.s) C (mpa s) 200 Bulk density (Kgm -3 ) 1234 a [30] b [Bayer Materials Science (Pittsburgh, PA)] Table 3.3. Reactivity profile for the processing of PMTAG Polyol rigid and flexible foams Cream time (s) Gel time (s) Rise time (s) Rigid Foam Flexible Foam As can be seen in Table 3.3 listing the cream time, gel time and rise time, the rigid foams formed relatively faster than the flexible foams. The difference in reactivity was attributed to the extra catalyst and co-catalyst (additional 1 part of both) and the addition of highly reactive glycerol in the rigid foam formulation (see Table 3.1). Higher catalyst concentration enabled shorter mix times and the further reactivity profiles of foaming processes. The addition of glycerol in the polymerization mixture for the rigid foam 105

131 formulation drives the crosslinking reaction by speeding the entire polymerization reaction compared to flexible foam formulations [33]. As shown in Figure 3.1a and 3.1b displaying representative pictures of PMTAG Polyol rigid Foam and PMTAG Polyol flexible Foam, respectively, the foams were white to very light yellow with a smooth surface. The flexible foams felt softer to the touch compared to the rigid foams. The color and smooth texture were preserved for all the foams regardless of density. (a) (b) Figure 3.1: Pictures of (a) Rigid PMTAG Polyol Foam, and (b) Flexible PMTAG Polyol Foam 3.3 Results and discussion FTIR Characterization of Foams The FTIR spectra of PMTAG Polyol rigid and flexible foams are shown in Figure 3.2. The formation of urethane linkages was evidenced by the characteristic broad absorption band of NH groups and of C=O of the urethane linkage at cm -1 and at 1700 cm -1, respectively [22].The band centered at 1519 cm -1 characteristic of C-N bonds also confirmed the formation of urethane bonds in the foams [34]. However, as shown by 106

132 the weak band at 2278 cm -1, some NCO groups were still present. This indicated that the isocyanate was not fully reacted [22, 28]. The overlapping peaks between 1710 and 1735 cm -1 suggested the presence of urea and isocyanurates in the PMTAG Polyol foams. The peak at 1417 cm -1 reveals the presence of small amount of isocyanurate trimers, indicating the occurrence of the trimerization reaction of diisocyanates during the foaming process. The stretching bands of the ester groups are particularly visible at 1744 cm -1 (C=O), cm -1 (O-C-C) and cm -1 (C-C(=O)-O). The stretching vibration of -C-H in -CH3 and -CH2 groups in the aliphatic chains were also visible at 2923 cm -1, and 2853 cm - 1 respectively [35]. Absorbance cm cm cm cm cm cm -1 (1) 0.05 (2) Wave Number (cm -1 ) Figure 3.2. Typical FTIR spectra of the PMTAG Polyol foams. (1) PMTAG Polyol Rigid Foam and (2) PMTAG Polyol Flexible Foam SEM analysis of PMTAG Polyol Foams Figure 3.3a and 3.3b show SEM images of the rigid and flexible PMTAG Polyol foams, respectively. Average cell size of rigid and flexible PMTAG polyol foams were

133 ± 40 µm and 386 ± 55 µm, respectively. The cell density from the SEM micrographs was ~21 cells per mm 2 for the rigid PMTAG polyol foams and ~18 cells per mm 2 and flexible PMTAG polyol foams. It was apparent from the SEM picture that the cells in the rigid PMTAG polyol foam were closed and uniformly arranged. The cells in the flexible foams were also closed but displayed non-uniform size (cell size ranges from 250 µm to 500 µm) and distribution. The highly compact and closed cell structure of the rigid PMTAG Polyol foams is due to their high cross linking density attributed to the presence of more primary hydroxyl groups by the addition of glycerin [36], while the absence of glycerin cross linker and the different rate of crosslinking of terminal versus internal hydroxyls present in the PMTAG polyol during flexible foam formulation resulted in less uniform cells [36]. Rigid and flexible foams with closed cell walls are suitable for thermal insulation applications [37]. (a) (b) Figure 3.3. Typical SEM micrographs of (a) Rigid PMTAG Polyol foams and (b) Flexible PMTAG Polyol Foam 108

134 3.3.3 Thermal Stability of Foams Figure 3.4a and 3.4b show the TGA/DTG profiles of rigid and flexible PMTAG polyol foams, respectively. The onset temperature of degradation of the rigid foam (RF) was consistently lower than that of the flexible foam (FF), whether determined at 1, 5 or 10% weight loss ( T 1% = 180 ºC and 216 ºC for RF and FF, respectively, T 5% = 253 ºC and 272 ºC for RF and FF, respectively, andt 10% = 275 ºC and 292 ºC for RF and FF, respectively). This may be due to the degradation of the short chain urethane structure from the low molecular weight glycerin cross linker. The DTG curves of both rigid and flexible Polyol foams showed four prominent peaks ( T Di, i=1-4, in Figure 3.4a and 3.4b) which indicate a multi stage decomposition process. The first peak centered at T D1= C, which involved a total weight loss of ~12 to 17 %, is related to the dissociation of urethane bonds, taken place either through the dissociation into isocyanate and alcohol, or the formation of primary or secondary amines, olefin and carbon dioxide [38, 39]. Weight Lost (%) (a) 296 o C 360 o C 434 o C 470 o C Temperature ( o C) DTG /%/ o C Weight Lost (%) (b) 303 o C 360 o C 434 o C 470 o C Temperature ( o C) DTGA /%/ o C Figure 3.4: TGA and DTG profiles of (a) PMTAG rigid foam and (b) PMTAG flexible foam. 109

135 The second and third DTG peaks (360 and 430 C) are associated with the decomposition of the soft segment (polyol back bone) into carbon monoxide, carbon dioxide, carbonyls (aldehyde, acid, acrolein) olefins and alkenes [39, 40]. These decomposition steps involved the largest weight loss with ~45-50 % of the total. The last DTG peak ( T D4 at ~ 470 C) is related to the decomposition of fragments such as esters or more strongly bonded fragments associated with the polyol backbone that occur at high temperature, and probably to the degradation of remaining carbonaceous materials from the previous step [41]. The rates of the urethane degradation were almost the same (maximum of ~0.40 %/ C) for the rigid and flexible PMTAG Polyol foams. Also the rates of each step of thermal degradation were similar for the rigid and flexible foams except in the last step at ~470 C where the rigid and flexible PMTAG Polyol foams displayed rates of 0.54 %/ C and 0.27%/ C, respectively. This may be due to the degradation of the left over fragments from the glycerol backbone used for the preparation of the rigid foams. The overall thermal stability of the PMTAG Polyol based foams is good and compares fairly well with the commercial foams and other vegetable based polyol foams [23, 33] DSC of Rigid and Flexible Foams DSC analysis was carried out to study the thermal phase transitions of the PU foams. Figure 3.5a and 5b show the DSC profiles obtained during the second heating cycle of the rigid and flexible PMTAG polyol foams, respectively. Three inflection points due to glass transitions ( T g low (RF: C, FF: C), Tg int (~34 C), Tg high (~50 C) in Figure 3.5a and 3.5b) were observed in the baseline of the thermograms of both rigid and flexible 110

136 PMTAG Polyol foams. No melting peaks were observed for any of the foams, indicating their high cross linking density. The Tg low of the rigid PMTAG Polyol foam was higher than that of the flexible PMTAG Polyol foam, probably because of higher crosslink density [29]. Recall that OH value was enhanced to 450 mg KOH/g by the addition of glycerine in the rigid foam formulation. Both rigid and flexible foam displayed almost same T at g int ~34 C and Tg high at ~50 C. The jump in heat capacity (ΔCp) was ~0.4 Jg -1 K -1 at Tg low, 0.1 Jg-1K -1 at Tg int, and Jg -1 K -1 at Tg high, suggesting that a large number of molecular chains were associated with the relaxation of the molecular motion of the polyol backbone [20]. The magnitude of molecular relaxation of the urethane segment ( T g high at ~50 C) was much smaller compared to Tg low due to the intramolecular and intermolecular crosslinking, which restricts the molecular motion of the hard segment of urethane [20]. Heat Flow (Wg -1 ) (a) Density-164 kgm -3 T g low T g int T g high Temperature ( o C) Heat Flow (Wg -1 ) (b) Density-160 kgm -3 T g low Tg int T g high Temperature ( o C) Figure 3.5. Typical DSC curves of (a) Rigid PMTAG Polyol Foam and (b) Flexible PMTAG Polyol Foam. 111

137 3.3.5 Compressive Strength of PMTAG Polyol Foams The mechanical properties of the foams were studied by the compressive stress-strain measurements. Figure 3.6a and 3.6b represent the compressive strength versus strain of the rigid and flexible PMTAG Polyol foams, respectively. A linear segment indicative of the elastic region of the rigid and flexible foams was observed at ~2-4% (Figure 3.6a) and ~8-10% (Figure 3.6b), respectively. The elastic region was followed by a long plateau in which the stress varied moderately. The plateau region in Figure 3.6a and 3.6b resulted from the buckling of the cell walls upon further compression of the foams [35]. The curve related to rigid foam of density 250 kg/m 3 (Figure 3.6a) displayed an elastic region only up to 2% strain with a maximum compressive strength at 5% deformation. Further compression of the rigid foam of density 250 kg/m 3 above 5% caused the breakage of the resultant foam (Figure 3.6a). This indicate that the cross-linking density and brittleness of the rigid foams may have increased with the increase in density [29]. The elastic region in the flexible foams observable at ~8-10% (Figure 3.6b) was followed by a long plateau up to ~25% strain in which the stress varied moderately and which indicates the buckling of the cells, and then by a relatively steep increase indicative of the collapse of the cells. Note that the elastic region as well as the plateau were more extended in the flexible foam than in their rigid foam counterparts, suggesting a very different structure of the walls. Each region is determined by some mechanism of deformation. The cell morphology such as cell size, cell wall thickness etc. has a critical role in the compressive strength of the foams [28]. The extent of bending of the cell walls during the compression process indicates the compressive strength of the foam such that the thickness of the cell wall, shape and size of the cells, type of cells (open or closed) etc., 112

138 have significant impact on the compressive strength [42]. Linear elasticity is controlled by cell wall bending and, in case of closed cells, by stretching of the cell walls. The plateau is associated with the collapse of the cells. When opposing cell walls touch, the further strain compresses the solid itself increasing stress rapidly, and giving the final so-called densification region [35]. Comperssive Strength (MPa) (a) Density (kg/m 3 ) Strain (%) Compressive Strength (MPa) (b) Density (kg/m 3 ) Strain (%) Figure 3.6. (a) Compressive strength versus strain curves of PMTAG Polyol foams (a) rigid foam (b) flexible foams. Figure 3.7a and 3.7b shows the density versus compressive strength of the rigid and flexible PMTAG polyol foams at different strain %. As seen in Figure 3.7a and 3.7b, the compressive strength of both rigid and flexible foams increased with increasing foam density. The highest compressive strength value for the rigid foam (2.5 MPa, Figure 3.7a) and for the flexible foam (1.07 MPa, Figure 3.7b) was obtained for the foams with the highest density, i.e., 250 kg/m 3 and 193 kg/m 3 respectively. The increase in density of the material increases the number of additional cross links and hence the compressive strength of the material [42]. 113

139 Compressive strength (MPa) (a) 6% 10% Density (kgm -3 ) Compressive strength (MPa) (b) 10% 25% Density (kgm -3 ) Figure 3.7. Density (kg/m 3 ) versus compressive strength (MPa) of PMTAG Polyol foams at 6% and 10% deformations (a) rigid foam (b) flexible foam. The compressive strength value of the rigid foams obtained from PMTAG Polyol are higher than those prepared from natural TAG oil polyols such as palm oil polyol [42], soybean oil polyol [7] and canola oil polyol [7]. Table 3.4 shows the compressive strength values of rigid foams obtained from palm oil [43], soybean oil [7] and canola oil polyol [7]. As can be seen in Table 3.4, the rigid foams prepared with polyols from palm oil and soybean oil presented compressive strengths which were half that of the rigid PMTAG polyol foam, understandably because the PMTAG polyol has less dangling chains and a relatively large amount of primary hydroxyl groups compared to the natural oils which possessed internal hydroxyl groups only. Even the rigid foam prepared from the canola oil polyol, which was free of dangling chains, presented a lower compressive strength at 10% deformation than the rigid PMTAG polyol foam of similar density. This may be due to the presence of highly reactive tetrols and hexols in the PMTAG polyol, which considerably amplified the cross linking density of the PMTAG polyol foams compared to canola oil polyol. 114

140 Table 3.4. Compressive strength of vegetable polyol based rigid foams from the literature[7, 43]. Rigid Foam from Density Compressive Polyol Specification (kg/m 3 ) Strength (MPa) OH value (mg KOH/g) dangling chains Terminal OH-groups Palm Oil Polyol Yes No Soybean Oil Polyol Yes No Canola oil polyol No Yes (triols) Recovery of Flexible Foams Figure 3.8a shows the percentage of recovery in thickness of flexible PMTAG Polyol foams as a function of time. The recovery in thickness of the flexible foams were measured after its maximum compression (65%) using a Vernier caliper. The recovery in thickness was recorded every minute for the first ten minutes, then after 1, 2, 24 and 48 h. In all the flexible foams, more than 60% recovery was obtained in less than 2 min, and ~ % after 5 min. At any given time, the flexible foams with highest density achieved the highest recovery, with a maximum of 91% for the flexible foam having the largest density (193 kgm -3 ). The recovery after 48 h of the flexible foams, increased linearly with 2 density (Figure 3.8b) ( R = ), with a slope of 0.5 % recovery per kgm -3. The flexibility of the foam was linked to the crosslinking density of the material. The compression of the low density flexible PMTAG polyol foams may rupture some of the cells due poor cell wall thickness. This prevents the easy and full recovery of the low density flexible foams. The increase in density of the flexible foam increases the number 115

141 of cross links and hence the cell wall thickness which allows the cells to withstand the stress without breakage. 100 (a) 100 (b) Recovery (%) Density (kg/m 3 ) Recovery (%) Time (min) Density (kgm -3 ) Figure 3.8. (a) Recovery of PMTAG Flexible Foam as a function of time (min); (b) Recovery of PMTAG Flexible Foam after 48 h as a function of density. Vegetable oil based polyols with only internal hydroxyl groups are widely used for flexible foam applications [44]. This is due to the less tightened cross link network formed by the internal OH polyols facilitated by the presence of dangling chains. However, the present data show that flexible foams with good recovery can be achieved from the PMTAG polyol even if it possesses terminal hydroxyl groups. The complex structure of PMTAG polyol allows their use in the preparation of functional rigid foams as well as high performing flexible foams. PMTAG polyol may also be partially substituted with commercial petroleum based polyols for the preparation of flexible foams with good physical properties similar to what was achieved with soybean oil polyol [15] and palm oil polyol [23]. 116

142 3.4 Conclusions 1-butene cross metathesized pal oil polyol (PMTAG Polyol), a mixture of diols, tetrols and hexols with 24.1 mol% terminal hydroxyl groups was found to be an ideal material for the preparation of polyurethane foams. Water blown rigid (densities ranging from 93 kgm -3 to 250 kgm -3 ) and flexible (densities ranging from 106 kgm -3 to 193 kgm -3 ) foams were successfully prepared from PMTAG polyol and fully characterized with FTIR, SEM, TGA and DSC. The cellular structure of the foams as evaluated from SEM comprised of small sized (rigid and flexible foams cell size: 270±40µm and 386±55 µm, respectively) and closed cells. Both the rigid and flexible PMTAG foams presented better thermal degradation stability compared to the commercially available vegetable-based and petroleum-based polyurethane foams. The rigid and flexible PMTAG Polyol foams displayed a multi-step glass transition attributable to the molecular motion of the polyol backbone at ~ -10 C and ~ -20 C and molecular motion of the urethane segments at higher temperatures (~ 34 C and ~50 C for the rigid and flexible, respectively. The rigid PMTAG polyol resulted in foams with higher compressive strengths compared to the highly unsaturated vegetable oil (soybean oil, canola oil) polyol derived rigid foams because of its terminal hydroxyls. The flexible foams produced from the PMTAG Polyol displayed good compressive strength with 90% recovery in thickness after compression. The good thermal stability and the closed cell structure suggests the suitability of the rigid and flexible foams for thermal insulation applications. The structural and physical properties of the foams of the present study substantiates the possibility of PMTAG polyol to compete favorably with the commercial bio-based as well as petroleum standard polyols for making polyurethane foams at an industrial scale. 117

143 Acknowledgements We would like to thank the Grain Farmers of Ontario, Elevance Renewable Sciences, Trent University, the GPA-EDC, Ontario Ministry of Agriculture, Food and Rural Affairs, Industry Canada and NSERC for financial support. 3.5 References [1] Szycher M. Szycher's handbook of polyurethanes: CRC press, [2] Guan J, Song Y, Lin Y, Yin X, Zuo M, Zhao Y, et al. Progress in study of nonisocyanate polyurethane. Industrial & Engineering Chemistry Research. 2011;50(11): [3] More AS, Gadenne B, Alfos C, Cramail H. AB type polyaddition route to thermoplastic polyurethanes from fatty acid derivatives. Polymer Chemistry. 2012;3(6): [4] Kong X, Narine SS. Physical properties of polyurethane plastic sheets produced from polyols from canola oil. Biomacromolecules. 2007;8(7): [5] Somani KP, Kansara SS, Patel NK, Rakshit AK. Castor oil based polyurethane adhesives for wood-to-wood bonding. International Journal of Adhesion and Adhesives. 2003;23(4): [6] Velayutham TS, Majid WHA, Ahmad AB, Kang GY, Gan SN. Synthesis and characterization of polyurethane coatings derived from polyols synthesized with glycerol, phthalic anhydride and oleic acid. Progress in Organic Coatings. 2009;66(4): [7] Narine SS, Kong X, Bouzidi L, Sporns P. Physical properties of polyurethanes produced from polyols from seed oils: II. Foams. Journal of the American Oil Chemists' Society. 2007;84(1): [8] John J, Bhattacharya M, Turner RB. Characterization of polyurethane foams from soybean oil. Journal of Applied Polymer Science. 2002;86(12): [9] Doyle EN. The development and use of polyurethane products: McGraw-Hill New York, NY, [10] Babb DA. Polyurethanes from Renewable Resources. In: Rieger B, Kunkel A, Coates GW, Reichardt R, Dinjus E, Zevaco TA, editors. Synthetic Biodegradable Polymers2012. p [11] David J, Vojtová L, Bednařík K, Kučerík J, Vávrová M, Jančář J. Development of novel environmental friendly polyurethane foams. Environmental Chemistry Letters. 2010;8(4):

144 [12] Firm MRCaC. Polyurethane Foam Market by Type (Flexible Foam, Rigid Foam), by End-User Industry (Bedding & Furniture, Building & Construction, Electronics, Automotive, Footwear, Packaging, Others), by Geography - Global Trends & Forecasts to 2020.marketsandmarkets.2015 ( [13] Desroches M, Escouvois M, Auvergne R, Caillol S, Boutevin B. From vegetable oils to polyurethanes: synthetic routes to polyols and main industrial products. Polymer Reviews. 2012;52(1): [14] Petrović ZS. Polyurethanes from vegetable oils. Polymer Reviews. 2008;48(1): [15] Zhang L, Jeon HK, Malsam J, Herrington R, Macosko CW. Substituting soybean oilbased polyol into polyurethane flexible foams. Polymer. 2007;48(22): [16] Tan S, Abraham T, Ference D, Macosko CW. Rigid polyurethane foams from a soybean oil-based polyol. Polymer. 2011;52(13): [17] Khoe TH, Otey FH, Frankel EN. Rigid urethane foams from hydroxymethylated linseed oil and polyol esters. J Am Oil Chem Soc. 1972;49(11): [18] Hu YH, Gao Y, Wang DN, Hu CP, Zu S, Vanoverloop L, et al. Rigid polyurethane foam prepared from a rape seed oil based polyol. Journal of Applied Polymer Science. 2002;84(3): [19] Babb DA. Polyurethanes from renewable resources. Synthetic Biodegradable Polymers: Springer; p [20] Tanaka R, Hirose S, Hatakeyama H. Preparation and characterization of polyurethane foams using a palm oil-based polyol. Bioresource Technology. 2008;99(9): [21] Ong A, Goh S. Palm oil: a healthful and cost-effective dietary component. Food & Nutrition Bulletin. 2002;23(1): [22] Chuayjuljit S, Sangpakdee T, Saravari O. Processing and properties of palm oil-based rigid polyurethane foam. Journal of The Minerals, Metals & Materials Society. 2007;17:7-23. [23] Pawlik H, Prociak A. Influence of palm oil-based polyol on the properties of flexible polyurethane foams. Journal of Polymers and the Environment. 2012;20(2): [24] Lida H, Sundram K, Siew WL, Aminah A, Mamot S. TAG composition and solid fat content of palm oil, sunflower oil, and palm kernel olein blends before and after chemical interesterification. Journal of the American Oil Chemists Society. 2002;79(11): [25] Santosa SJ. Palm oil boom in Indonesia: from plantation to downstream products and biodiesel. CLEAN Soil, Air, Water. 2008;36(5 6):

145 [26] Ong AS, Goh S. Palm oil: a healthful and cost-effective dietary component. Food & Nutrition Bulletin. 2002;23(1): [27] Zlatanic A, Petrovic ZS, Dusek K. Structure and properties of triolein-based polyurethane networks. Biomacromolecules. 2002;3(5): [28] Narine SS, Yue J, Kong X. Production of polyols from canola oil and their chemical identification and physical properties. Journal of the American Oil Chemists' Society. 2007;84(2): [29] Guo A, Demydov D, Zhang W, Petrovic ZS. Polyols and Polyurethanes from Hydroformylation of Soybean Oil. Journal of Polymers and the Environment. 2002;10(1): [30] Prasanth S.Pillai SL, Laziz Bouzidi and Suresh S. Narine. 1-Butene Metathesized Palm Oil & Its Polyol derivatives: Structure, Chemical composition and Physical Properties. Submitted to Industrial Crops and Products [31] Tate PM, Talal S. Compressive properties of rigid polyurethane foams. Polymers & Polymer Composites. 1999;7(2): [32] Ashida K. Polyurethane and related foams: chemistry and technology: CRC press, [33] Guo A, Javni I, Petrovic Z. Rigid polyurethane foams based on soybean oil. Journal of Applied Polymer Science. 2000;77(2): [34] Piszczyk Ł, Strankowski M, Danowska M, Hejna A, Haponiuk JT. Rigid polyurethane foams from a polyglycerol-based polyol. European Polymer Journal. 2014;57: [35] Gu R, Konar S, Sain M. Preparation and characterization of sustainable polyurethane foams from soybean oils. Journal of the American Oil Chemists' Society. 2012;89(11): [36] Campanella A, Bonnaillie LM, Wool RP. Polyurethane Foams from Soyoil-Based Polyols. Journal of Applied Polymer Science. 2009;112(4): [37] Prociak A, Pielichowski J, Sterzyñski T. Thermal diffusivity of polyurethane foams measured by the modified ångström method. Polymer Engineering & Science. 1999;39(9): [38] Javni I, Petrović ZS, Guo A, Fuller R. Thermal stability of polyurethanes based on vegetable oils. Journal of Applied Polymer Science. 2000;77(8): [39] Shufen L, Zhi J, Kaijun Y, Shuqin Y, Chow W. Studies on the thermal behavior of polyurethanes. Polymer-Plastics Technology and Engineering. 2006;45(1):

146 [40] Gryglewicz S, Piechocki W, Gryglewicz G. Preparation of polyol esters based on vegetable and animal fats. Bioresource Technology. 2003;87(1):35-9. [41] Lin B, Yang L, Dai H, Hou Q, Zhang L. Thermal analysis of soybean oil based polyols. Journal of Thermal Analysis and Calorimetry. 2009;95(3): [42] Thirumal M, Khastgir D, Singha NK, Manjunath B, Naik Y. Effect of foam density on the properties of water blown rigid polyurethane foam. Journal of Applied Polymer Science. 2008;108(3): [43] Chian K, Gan L. Development of a rigid polyurethane foam from palm oil. Journal of Applied Polymer Science. 1998;68(3): [44] Banik I, Sain M. Water blown soy polyol-based polyurethane foams of different rigidities. Journal of Reinforced Plastics and Composites

147 4 Fractionation Strategies for Improving Functional Properties of Polyols and derived Polyurethane Foams from 1-butene Metathesized Palm Oil Introduction Palm oil is one of the most abundant and inexpensive renewable commodity oils in the world, making it an economical alternative feedstock for the polymer industry [1]. However, its saturation level (~50% saturated fatty acids) limits the hydroxyl value of polyols derived from the native oil [2]. Furthermore, because of the internal position of its double bonds, native palm oil produces polyols with dangling chains at the unsaturated sites which after polymerization leads to incomplete crosslinking and imperfections in the polymer network [3, 4]. Several strategies have been employed to address these handicaps, including the recent cross metathesis of palm oil with 1-butene [5]. Olefin cross metathesis enables the shortening of unsaturated fatty acids at the location of the double bonds, producing low molecular weight TAG products with terminal double bonds: structures that can yield polyols with primary hydroxyls on functionalization 2 A version of this chapter is filed as a US provisional patent: U.S. Provisional Patent Application # , (filed January, 2015), Polyols from the Fractions of Metathesized Triacylglycerols and Polyurethanes from such Polyols and Their Physical Properties, S.S. Narine, Prasanth. K. S. Pillai, S.Li, L.Bouzidi and A.Mahadevari and Submitted for a publication in Industrial Crops and Products 122

148 [5-7]. Such terminal hydroxyl polyols are free of pendant chains arising from the unsaturated fatty acid moieties, with reduced steric hindrances and dangling chains in subsequent polyurethane networks [8]. However, since metathesis does not affect the saturated moieties of the natural oil, the saturated fatty acid moieties of the native oil (~50 %) still limit the hydroxyl number and provides steric hindrances and dangling chains in resulting polyurethanes. The starting material of the present work derives from 1-butene cross metathesis of palm oil (PMTAG), stripped of short chain olefins, which has been previously well characterized [5]. PMTAG comprises approximately 25% terminal double bonds, 28% shortened unsaturated fatty acids, and ~47% of saturates inherited from the natural oil. PMTAG was easily converted into polyols by standard epoxidation and hydroxylation [5] which were then used to make improved rigid and flexible polyurethane foams [8]. However, although the compressive strength of the foams was significantly enhanced due to the reduction of dangling chains associated with the terminal unsaturated fatty acids, undesirable long pendent chains were still present due to the relatively large number of saturates left from the natural oil. Opportunely, PMTAG is comprised of two relatively separate portions akin to the stearic and oleic portions of the natural palm oil, indicating that it can be separated into high and low melting fractions. If a facile fractionation is possible, the low melting portion should contain less of the highly saturated components and therefore should make a feedstock which would help mitigate the problems associated with the plasticizing action of the dangling chains in rigid foams. The material should also be more easily processed because of a lower melting temperature and should present less 123

149 steric hindrance during functionalization to produce polyol and also in crosslinking process to form polyurethanes. Crystallization is one of the most effective and economical means for fractionating vegetable oils [9]. Crystallization fractionation consists of two steps, first the cooling of the liquid oil using specific processing conditions to a crystallization temperature and then removal of the solid fat from the liquid oil [10]. During the cooling process, the high melting components of the oil crystallize first and these can be removed from the liquid oil via filtration or sedimentation. The parameters of an effective fractionation by crystallization are determined by the cooling rate, the crystallization temperature and the crystallization time [11]. Fractionation can be entirely from the melt (dry) or can be solvent mediated. Solvent aided crystallization, although more expensive, is more efficient and allows for facile filtration since the viscosity of the liquid oil is reduced when a solvent is present [11]. Furthermore, it can be advantageous if the solvent was a part of the further transformation of the material, such as in the synthesis of polyols. For this reason both solvent and dry crystallization methods were used to fractionate PMTAG in an attempt to optimize yield and composition of the fractions, particularly with respect to the synthesis of polyols and rigid polyurethane foams. Several studies regarding the fractionation of palm oil by dry as well as solvent aided crystallization have been published [12-14]. The present work reports on the fractionation of PMTAG and the synthesis of polyols from the fractions. The fractionation was performed by dry as well as solvent mediated crystallization for optimum yield and quality of the liquid fraction. Quality here refers to maximum unsaturation content. The polyols were synthesized by standard epoxidation and hydroxylation reactions, and characterized 124

150 chemically and physically to determine their suitability as monomers for the preparation of polyurethane foams. The rigid and flexible foams were prepared with similar densities (~160 kg m -3 ) to allow for comparison. The urethane linkage of the foams was confirmed by FTIR. Their morphology, thermal decomposition and thermal transition behaviours were studied by scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The compressive strength of the foams were determined with a texture analyzer. 4.2 Materials and Methods Materials PMTAG was provided by Elevance Renewable Sciences (ERS, Bolingbrook, II). Dichloromethane (DCM), ethanol (anhydrous), toluene, potassium hydroxide, and sodium thiosulfate were purchased from ACP Chemical Int. (Montreal, Quebec, Canada) and used without further treatment. Formic acid (88 wt %) and hydrogen peroxide (30 wt% in H2O), iodine monochloride (95%), potassium iodide (99%), dibutin dilaurate (DBTDL), glycerin (99.5 %) and phenolphthalein were purchased from Sigma-Aldrich Canada Co. (Oakville, Ontario, Canada). Perchloric acid (70%), N, N-dimethylethanolamine (DMEA) was purchased from Fisher Scientific, USA, diphenylmethane diisocynate (MDI) from Bayer Materials Science (Pittsburgh, PA), and polyether-modified surfactant (TEGOSTAB B- 8404) from Goldschmidt Chemical Canada. HPLC grade solvents were obtained from VWR International, Mississauga, ON. 125

151 4.3 Chemistry Characterization Techniques Titrimetric Methods (OH value, Acid value, Iodine value) Iodine and acid values of SF- and LF- PMTAG were determined according to ASTM D and ASTM D , respectively. OH and acid values of the polyols were determined according to ASTM S and ASTM D , respectively Proton Nuclear Magnetic Resonance Spectroscopy ( 1 HNMR) 1 H-NMR spectra were recorded CDCl3 on a Varian Unity-INOVA at MHz using an 8.6 μs pulse with 4 transients collected in points. Datasets were zero-filled to points and a line broadening of 0.4 Hz was applied prior to Fourier transforming the sets. 1 H chemical shifts are internally referenced to CDCl3 (7.26 ppm). The spectra were processed using spinwork NMR Processor, version Fourier Transform Infrared Spectroscopy (FTIR) FTIR spectra of the foams were obtained using a Thermo Scientific Nicolet 380 FT- IR spectrometer (Thermo Electron Scientific Instruments, LLC, USA) equipped with a PIKE MIRacle TM attenuated total reflectance (ATR) system (PIKE Technologies, Madison, WI, USA.). Foam samples were loaded onto the ATR crystal area and held in place by a pressure arm. The spectra were acquired over a scanning range of cm - 1 for 32 repeated scans at a spectral resolution of 4 cm Physical Characterization Techniques Thermogravimetric Analysis (TGA) The TGA measurements were carried out on a Q500 model (TA Instruments, DE, USA) under dry nitrogen of 40 ml/min for balance purge flow and 60 ml/min for sample 126

152 purge flow. Approximately mg of sample was loaded into the open TGA platinum pan then heated from 25 C to 600 C at a constant rate of 10 C/min Differential Scanning Calorimetry (DSC) DSC was performed on a Q200 model (TA Instruments, New Castle, DE) under a nitrogen flow of 50 ml/min. Samples between 3.5 and 6.5 (± 0.1) mg were run in hermetically sealed aluminum DSC pans. DSC measurements of the PMTAG fractions and PMTAG Polyols were run in standard mode. The sample was equilibrated at 90 C for 10 min to erase thermal memory, and then cooled at 5.0 C/min to -90 C where it was held isothermally for 5 min, and subsequently reheated at 5.0 C/min to 90 C. PMTAG was also cooled at 0.1 C/min and 1 C/min to investigate the effect of cooling rate on its crystallization behavior. In order to obtain a better resolution of the glass transition, the foams were investigated using modulated DSC following the ASTM E standard. The sample was first equilibrated at 25 C and heated to 150 C at 10 C/min (first heating cycle), held at that temperature for 5 min and then cooled down to -90 C at 10 C/min, and subsequently reheated to 150 C at the same rate (second heating cycle). Modulation amplitude and period were 1 C and 60 s, respectively. The TA Universal Analysis software version 5.4 was used to analyze the DSC thermograms and extract the peak characteristics. Characteristics of non-resolved peaks were obtained using the first and second derivatives of the differential heat flow. 127

153 4.4.3 Rheology A temperature-controlled Rheometer (AR2000ex, TA Instruments, DE, USA) fitted with a 40 mm 2 steel geometry was used to measure the viscosity and flow property of the PMTAG fractions and PMTAG Polyols. Temperature control was achieved by a Peltier attachment with an accuracy of 0.2 C. Shear Stress was measured at each temperature by varying the shear rate from 1 to 1200 s -1. Measurements were taken at 10 C intervals from high temperature (100 C) to 10 C below the DSC onset of crystallization temperature of each sample. The viscosity versus temperature data were collected at 200 s -1 using the constant temperature rate method (1.0 C/min). Data points were collected from each sample s melting point up to 110 C at intervals of 1 C. The viscosity obtained in this manner was in very good agreement with the measured viscosity using the shear rate/share stress. The shear rate shear stress curves were fitted with the Herschel-Bulkley equation (Eq. 2.1), a model commonly used to describe the general flow behavior of liquid materials, including those characterized by a yield stress. n 0 K Eq. 4.1 Where denotes the shear stress, 0 is the yield stress below which there is no flow, K the consistency index and n the power index. n depends on constitutive properties of the material. For Newtonian fluids n = 1, shear thickening fluids, n 1 and for shear thinning fluids, n

154 4.4.4 Scanning Electron Microscopy (SEM) A scanning electron microscope (SEM), model Tescan Vega II, was used under standard operating conditions (10 kev beam) to examine the pore structure of the foams. A sample of approximately 2 cm x 2 cm and 0.5 cm thick was cut from the centre of a 60- mm diameter and 36-mm long specimen. The sample was coated with a thin layer of carbon (~30 nm thick) using an Emitech K950X turbo evaporator to ensure electrical conductivity in the SEM chamber and prevent the buildup of electrons on the surface of the sample. All images were acquired using a secondary electron detector to show the surface features of the sample Compressive Strength The compressive strength of the foams was measured at room temperature using a texture analyzer (Texture Technologies Corp, NJ, USA). Samples were prepared in cylindrical Teflon molds of 60-mm diameter and 36-mm long. The cross head speed was 3.54 mm/min with a load cell of 750 kgf. The load was applied until the foam was compressed to approximately 15% of the original thickness for the rigid foam, and 65% for the flexible foam. 4.5 Fractionation of PMTAG by dry and solvent mediated crystallization The fractionation protocol for PMTAG was informed by its cooling thermal transition behavior. Figure 4.1 shows the DSC cooling thermograms of PMTAG obtained with 0.1 C/min, 1.0 C/min and 5.0 C/min. The corresponding thermal data (onset ( TOn ), offset ( T Off ) and peak ( T p ) temperatures) are listed in the Appendix in Table A2. 129

155 0.75 (a) P1 P2 Heat Flow (Wg -1 ) (Exo up) P3 Rate ( o C/min) Temperature ( o C) Figure 4.1. Crystallization thermograms of PMTAG obtained at 0.1 C/min, 1 C/min and 5 C/min. As can be seen, all the thermograms of Figure 4.1 present three distinguishable peaks (P1, P2 and P3 in Figure. 4.1) indicative of three different crystallization events representing a high and two low temperature crystallizing portions [15]. The lowest temperature peak (P3) was well separated in the 0.1 C/min experiment only. Although P3 is related to a specific well-defined molecular portion of PMTAG (the lowest crystalizing portion), it cannot be easily separated from the main low temperature fraction expressed by P2. In fact, the DSC trace reveals the presence of a high and a low temperature crystallizing portions reminiscent of the stearin and olein of the natural palm oil [5, 16]. The combined P2 and P3 are the recording of the olein-like portion of PMTAG and P1 the recording of its stearin-like portion. The data from Figure 4.1 motivates a cooling protocol and crystallization temperature ranges that would be optimal for the separation of PMTAG 130

156 into a high and low melting fractions. As is indicated by the DSC thermograms, a better separation would be obtained with the slowest cooling of PMTAG. One then can choose an isothermal crystallization temperature ( T C ) where only the nucleation of the high crystallizing molecules (stearin-like portion) are occurred, i.e., above at least the offset of the first peak to avoid the formation of the low melting crystals (olein-like portion). The isothermal crystallization time period ( t C ) should be chosen to allow for the stearin-like portion to solidify. The choice of T C and C t will dictate the yield and quality of the separation provided a proper filtration of the solids from the liquid can be achieved. The same considerations are valid for both the dry and solvent crystallization, taking into account their actual crystallization parameters and more importantly, the boiling point of the solvent, in our case 39.6 C for DCM. Four (04) dry fractionation experiments (method labeled D), and one (01) solvent mediated crystallization experiment (method labeled S) were used to optimize the fractionation of PMTAG with a compromise between quality and yield of the liquid fraction. The details of the fractionation experiments are presented in Table Dry crystallization experiments Four sets of fractionation experiments were conducted with the dry crystallization method (F1-F4 in Table 4.1). Between 200 and 260 g of melted PMTAG was equilibrated at 90 C in a round bottom flask placed in a temperature controlled water bath (Julabo FP50-ME, Julabo USA Inc., Vista, CA). The sample was cooled down at a prescribed rate (0.05 or C/min) to T C at which point it was crystallized isothermally under vigorous 131

157 stirring (500 rpm) during t C. The solid fraction was filtered from the liquid with filter paper (Fisherbrand, P5) and with the help of a vacuum pump (BUCHI V-700, Switzerland) Solvent Mediated Crystallization Experiment For the solvent mediated fractionation (F5 in Table 4.1), 5 kg of melted PMTAG was mixed under gentle stirring with 5 kg (3.8L) of DCM (PMTAG to DCM ratio of 1:1 (wt/wt)) in a preheated (37 C) 20-L jacketed reactor (Heb Biotechnology Co., Ltd, Xi an, China). The reactor was kept at 37 C with a connected temperature controlled circulator (Hack Phoenix II P1 Circulator, Thermo Electron, Karlsruhe, Germany) until the dissolution was complete. The PMTAG was then brought under stirring to a temperature of 2 C at which the stirring was turned off and the mixture was left to crystallize isothermally for 24 h allowing for the stearin-like portion of PMTAG to crystallize and eventually sediment. The crystallized material was then filtered from the liquid easily and very effectively with filter paper (Fisherbrand, P8, 15 cm) and vacuum (300 Torr). Table 4.1. Fractionation data of PMTAG. a T C : Crystallization temperature; bt C : isothermal crystallization time Experiment Mass (g) Cooling Rate ( C/min) at C ( C) bt C (h) LF: Yield (wt %) F F F F F Quiescent

158 4.6 Synthesis of the Polyols Polyols were synthesized from LF- and SF-PMTAG in a two-step reaction; epoxidation by formic acid and hydrogen peroxide (H2O2), followed by hydroxylation using water and perchloric acid (HClO4) as the catalyst following a previously reported method, [5]. The chemical route is described in Scheme 4.1 Scheme 4.1. Synthesis route of polyols from the liquid and solid fraction of PMTAG (n=0, 2, 8; m=11 to 20). This is a well-established economical route to produce polyols with maximum hydroxyls. In this method the double bonds are converted into oxirane moieties and the epoxy groups are converted into hydroxyl groups by ring opening reaction with suitable reagents like HClO4 and H2O to give the polyol. The polyols produced from liquid and solid fractions are labeled LF-Polyol, and SF-Polyol, respectively. 133

159 4.6.1 Epoxidation Formic acid (88%; 200g) was added to a solution of fractionated PMTAG (200 g) in DCM (240 ml). The mixture was cooled to 0 C in an ice bath, and hydrogen peroxide (30 %, 280 g) was added drop wise while stirring with a mechanical stirrer (500 to 600 rpm). After the addition of hydrogen peroxide, the mixture was raised to 50 C and kept at this temperature with stirring until the reaction was complete. The reaction was monitored by a combination of TLC and 1 H-NMR, and was deemed complete after 48 h. The reaction mixture was then diluted with 250 ml of DCM, washed with water (200 ml 2), and then with saturated sodium hydrogen carbonate (200 ml 2), and again with water (200 ml 2). The resulting epoxide was rotary evaporated to remove the solvent, and then was dried over anhydrous sodium sulphate Hydroxylation Approximately 200 g of crude fractionated PMTAG epoxide was dissolved at room temperature in a 500 ml mixture of THF/H2O (3:2) containing 14.5 g of perchloric acid. The resultant mixture was stirred at room temperature for 36 h, a time after which the reaction which was monitored by a combination of TLC and 1 H-NMR was deemed complete. The reaction mixture was poured into 240 ml water and extracted with CH2Cl2 (2 240 ml). The organic phase was washed with water (2 240 ml), followed by 5% aqueous NaHCO3 (2 200 ml), and then with water again (2 240 ml), and then dried over Na2SO4. After removing the drying agent by filtration, the solvent was removed with a rotary evaporator and further dried by vacuum overnight, giving a light yellow greaselike solid. 134

160 4.7 Polymerization Method The formulation recipes for the preparation of rigid and flexible polyurethane foams from LF-Polyol are provided in Table 4.2. The ingredient amounts are based on 100 parts by weight of polyol. The amount of MDI was calculated based on an isocyanate index 1.2 (NCO to OH ratio of 1.2 to 1). All the ingredients, except MDI, were weighed into a beaker, and pre-weighed MDI was added to the beaker using a syringe. The resulting mixture was mechanically mixed vigorously for 10 to 20 s. the mixture was immediately transferred into a cylindrical Teflon mold (60 mm diameter and 35 mm long) previously greased with a silicone release agent, and then sealed with a hand tightened clamp. The sample was cured for four (4) days at 40 C and post cured for one (1) day at room temperature. Table 4.2. Formulation Recipes for Rigid and Flexible Foams Parts by weight Ingredient Rigid Foams Flexible Foams LF-Polyol OH: NCO ratio 1:1.2 1:1.2 Glycerin Water 2 2 Surfactant 2 2 Catalyst Co-catalyst

161 4.8 Results and Discussion Results of the fractionation of PMTAG DSC investigation of the fractions confirmed that the fractionation was generally effective and that a wide range of compositions for the liquid and the solid fractions can be obtained by tuning the experimental parameters. The DSC cooling and heating thermograms obtained in experiment F2 representative of the liquid and solid fractions of PMTAG are presented in Figures 4.2a and 4.2b, respectively. The DSC thermograms of the liquid and solid fractions obtained by the different fractionation methods are provided in the Appendix in Figures. A5 A6 and the corresponding thermal characteristics in Table A3. (a) (b) LF Heat Flow (Wg -1 ) (Exo up) SF Heat Flow (Wg -1 ) (Exo up) SF LF Temperature ( o C) Temperature ( o C) Figure 4.2. Typical DSC thermograms of the liquid (LF) and solid fractions (SF) of PMTAG. (a) cooling and (b) heating (both at 5 C/min) 136

162 As can be seen in Figure 4.2a, the cooling thermograms of the solid fractions displayed both the high and low temperature exotherms, indicating that it retained a part of the olein-like portion of PMTAG. The DSC data of the LF- and SF-PMTAG are provided in the Appendix Table A4. The enthalpy of the exotherm relevant to the olein-like part of the solid fraction varied depending on the experiment but its onset of crystallization remained constant and equal to what was measured for the starting PMTAG (see Figure 4.1). This indicates that the liquid was not selectively trapped in the solid. F1, F2 and F5 experiments yielded liquid fractions comprising some of the stearin portions of the PMTAG. However, as evident from the leading peak of LF in Figure 4.2a, the onset of crystallization (~14 C) as well as the enthalpy were much lower than those of PMTAG, indicating that the highest crystallizing temperature compounds of the stearin portion were effectively removed. F3 and F4 experiments yielded liquid fractions comprising the olein portion of PMTAG only but with relatively low yields (~37 %wt/wt and 22 %wt/wt, respectively, Table 4.1). The onset temperature of crystallization of the liquid fractions shifted to sub ambient temperatures, and their heating thermograms were missing the highest melting peaks at ~ 47 C (Figure 4.2b). This indicates that the stearin portion of the liquid fraction was depleted from the highest crystallizing components of PMTAG and enriched with the unsaturated and the short saturated moieties. The acid value of the SF- and LF- PMTAG fractions were all lower than 0.8 mg KOH/g, indicating a very low free fatty acid content. The iodine value (IV) of the solid fractions ranged from ~35 to ~36, much less than the 52 IV value of PMTAG, indicating the extent at which the fraction was depleted from the unsaturated elements of PMTAG. 137

163 The liquid fractions of the PMTAG presented an IV of ~60 to ~61, higher than PMTAG, which confirms that enrichment of the liquid fractions with olein-like molecules. F2 which provided the liquid fraction with the best compromise between the decrease in onset temperature of crystallization (13.5 C) and yield (45 %wt/wt) and which presented the highest iodine value and lowest acidity value was selected for further analysis and use for the synthesis of polyols. The selected fractions simply labelled LF-PMTAG and SF-PMTAG for the liquid and solid fractions of PMTAG, respectively. The corresponding polyols are also simply labeled LF-Polyol and SF-Polyol, respectively H-NMR Characterization of the PMTAG fractions 1 H-NMR spectra and corresponding 1 H-NMR chemical shifts of LF- and SF- PMTAG are provided in the Appendix in Figure A7-A8 and Table A5, respectively. As expected, LF- and SF- PMTAG displayed the same chemical shifts observed for PMTAG [5]. Scheme 4.2 represents the possible structures of LF- and SF-PMTAG as revealed by 1 H-NMR. The fatty acid profiles calculated based on the relative area under the characteristic 1 H-NMR peaks are presented in Table 4.3. the terminal double bond, internal double bond and saturated fatty acid contents were calculated based on the integrated protons under the ppm, δ ppm and ppm peaks, respectively. Note that based on their very low acid value (<1 mg KOH/g), the analysis of the 1 H-NMR of LF and SF-PMTAG was performed assuming that only TAG structures were present. 138

164 Scheme 4.2. Possible TAG structures in LF-and SF-PMTAG. n=0, 2, 8; m= 11 to 20. Table 4.3. Fatty acid profile of SF-PMTAG and LF-PMTAG calculated based on the relative area under the characteristic 1 H-NMR peaks assuming TAG structures only. The PMTAG data are provided for comparison purposes. TDB: Terminal double bonds; IDB: Internal double bonds; FA: Fatty acid; SFA: Saturated fatty acid FA with TDB (mol%) FA with IDB (mol%) SFA (mol%) n=0 in Scheme 4.1 n=3 in n=8 in Total Scheme 4.1 scheme 4.1 LF-PMTAG SF-PMTAG PMTAG LF-PMTAG comprised more structures with internal double bonds (~31 mol%) and structures with terminal double bonds (~21 mol%) than SF-PMTAG (~26 mol% and ~20 mol%, respectively). LF-PMTAG also comprised less saturated fatty acid chains than SF- PMATG (~48 mol% compared to ~53 mol%, Table 4.3). The relatively large decrease in 139

165 the onset temperature of crystallization and offset temperature of melting of LF-PMTAG is attributable also to a relatively higher number of TAGs with short saturated moieties including trisaturated TAGs of the starting material such as trimyristoylglycerol (MMM) and 1,2-dimyristoyl-3-palmitoyl-sn-glycerol (MMP) Characterization of the polyols synthesized from LF- and SF-PMTAG The polyols obtained from the liquid and solid fractions (LF-Polyol and SF-Polyol, respectively) presented OH values of 184 and 136 mg KOH/g, respectively. Their acid value was less than 4 mg KOH/g. These chemical characteristics are very suitable for the further transformation of the polyols into polyurethane foams. The OH value of LF-Polyol is understandably much higher than the OH value measured for the polyol obtained from the non-fractionated PMTAG. The structure of the LF-Polyol and SF-Polyol was determined based on the analysis of 1 H-NMR characteristic chemical shifts. The 1 H-NMR data are provided in the Appendix in Figures A9-A10 and Table A6. The 1 H-NMR presented the peak characteristic of the OH groups (δ ppm) but not the peak of the epoxides (δ ppm) indicating that the conversion to hydroxyl groups was complete. The polyols exhibited the chemical shifts of methylene at δ 5.27 ppm and ppm, and methine protons at δ ppm typical of TAG glycerol backbones. Furthermore, the peaks the methine protons presented a ratio of 1:1 indicative of the integrity of the TAG backbone, confirming that the hydrolysis of the TAG was avoided. Internal and terminal hydroxyls (diols, tetrols and hexols) were detected in both LF-and SF-Polyols. The amount of hydroxyls as estimated by 1 H-NMR was ~47 %mol in SF-Polyol and~52 %mol in LF-Polyol. The percentage of terminal hydroxyls in both LF- and SF-Polyols was ~21%. There were more non-terminal hydroxyls 140

166 in LF-Polyol than in unfractionated PMTAG Polyol (so called PMTAG Polyol) or SF- Polyol. The possible structures of the polyols are shown in Scheme 4.3. Scheme 4.3. Possible structures of LF- and SF-Polyols (n= 0, 2, 8; m=11 to 20) Thermal Decomposition of LF- and SF-Polyols The DTG profiles of LF-and SF-Polyols are shown in Figure 4.3. The corresponding data are provided in the Appendix in Table A7. The DTG data indicate that the polyols synthesized from the fractions undergo degradation mechanisms similar to the polyols made from PMTAG [5]. The DTG curves presented a weak and broad peak centered at ~ 220 C followed by a large peak at C and a small shoulder at ~ 450 C ( T D1, T D2, and T D3, respectively, in Figures. 4.3) indicating three steps of degradation. The first step which involved ~1 to 3% weight loss may be due to the loss of hydroxyl groups [17]. The second DTG peak, where ~ 50-67% weight loss was recorded, is associated with the breakage of the ester bonds [18]. Note that this mechanism of degradation was also dominant in the starting LF- and SF-PMTAG. The small DTG shoulder at ~ 450 C ( T D 3 141

167 in Figure. 4.3) indicate the decomposition high temperature fragments and of remaining carbonaceous materials from the previous steps [17]. T D2 DTG (% o C -1 ) SF T D1 T D3 LF Temperature ( o C) Figure 4.3. DTG of LF- and SF-Polyols Crystallization and Melting Behavior of LF- and SF- Polyols The crystallization and heating profiles (both at 5 C/min) of LF- and SF-Polyols are shown in Figures 4.4a and 4.4b, respectively. The corresponding thermal data are provided in the Appendix listed in Table A8. As can be seen in Figure 4.4a, the three peaks in the cooling thermograms of LF- and SF-Polyols (P1, P2 and P3 in Figure 4.4a), although poorly separated, mirror the peaks observed in the thermograms of LF- and SF- PMTAG indicating that the two-portion distribution of the starting fractions was preserved in the polyols. Such a DSC trace indicates that although possible, one cannot separate easily the high and low melting portions of the polyols. One can also note that the lowest temperature peak (P3 in Figure 4.4a) is much more prominent in the polyols compared to their starting material indicating a particular effect of the OH groups on the transition behavior of the different collections of polyol molecules. 142

168 The cooling and heating thermograms of the polyol synthesized with the solid fractions of PMTAG shows significant differences with those of the liquid Fraction. SF- Polyol crystallized at 5 C higher temperature than LF-Polyol and presented extra peaks at the high temperature side of the thermogram (P1 and P1 of SF at the right side of P1 of LF in Figure 4.4a). The endotherms of its melting trace were visibly separated contrary to the greatly overlapped endotherms of LF-Polyol. The crystallization traces of the polyols are directly related to their unbalanced olein-like/ stearin-like composition, wherein, SF- Polyol comprised the saturated TAGs (P1 in Figure 4.4a), partially functionalized TAGs with long saturated moieties (P1 in Figure 4.4a) as well as higher level hydroxyls such as tetrols and hexols. The melting behavior of the polyols is directly related to the degree of separation in crystallization temperature of families of molecules present. The melting peaks of SF- Polyol are well separated contrary to those of LF-Polyol because of large difference between the stearin-like molecules (as represented by P1 in Figure 4.4a) and the functionalized molecules from the olein-like molecules of SF-PMTAG. The occurrence of a prominent exotherm during the heating of SF-Polyol is an indication of a crystallization mediated by melt that resulted in the shifting of its offset temperature to ~50 C closer to ~45 C of LF-Polyol which did not experience a detectable exotherm. This relatively intense transformation was probably experienced by a substantial number of partially functionalized TAGs in SF-Polyol. The melting point of LF-Polyols as determined by its offset temperature of melting was ~45 ºC, a value close to that of PMTAG Polyol: 47 ºC [5]. This indicates that similar reaction temperatures and equipment can be used for the further transformation of LF-Polyol into polyurethane foams. 143

169 (a) (b) Heat Flow (Wg -1 ) (exo up) P1 P2 P3 P1 P2 P3 SF LF Heat Flow (Wg -1 ) (endo down) G1 G2 SF LF Temperature ( o C) Temperature ( o C) Figure 4.4. DSC thermograms of LF- and SF-Polyols obtained from the liquid fractions and solid fractions of PMTAG during (a) Cooling (5.0 C/min), and (b) subsequent heating (5 C/min) Flow Behavior and Viscosity of LF- and SF-PMTAG Polyols Selected shear stress versus shear rate curves recorded for LF- Polyol between 30 ºC to 100 ºC are shown in Figure 4.5 a. Fits to the Herschel-Bulkley model are included in the figure (dashed lines in Figure. 4.5a). Evident from Figure 4.5a, share rate shear stress curves of the LF Polyol were linear for the whole shear rates range, except at 40 ºC where it was linear below 500 s -1 only, indicating Newtonian behavior. Similar curves indicating a Newtonian flow within 50 ºC to 90 ºC were obtained for SF-Polyols (data not shown). The data collected below the onset of crystallization of LF-Polyol (~29 C) and SF-Polyol (~32 C) indicated that the sample has crystallized. Figure 4.5b presents the viscosity versus temperature plot obtained during cooling at 1 C/min for LF- and SF-Polyols. As 144

170 evident from the figure, the viscosity of LF-Polyol was higher at all temperatures with the difference decreasing with increasing temperature. Although relative molecular size could have played a role, this difference is mainly attributable to a higher number of hydroxyls in LF-Polyol, as manifest in the OH value. Note that the viscosity of LF-Polyol is also higher than that of PMTAG Polyol [5, 19], also attributable to the higher OH value of LF- Polyol compared to PMTAG Polyol [20]. Shear Stress (Pa) (a) 40 o C T ( o C) Viscosity (Pa.s) (b) SF LF Shear Rate (s -1 ) Temperature ( o C) Figure 4.5. (a) Shear rate- shear stress of LF-Polyol), (b) viscosity versus temperature of LF- and SF-Polyols. Solid lines in (a) are fits to the Herschel-Bulkley model (Eq. 4.1). 4.9 Polyurethane Rigid and Flexible Foams Because of its high OH value, favorable thermal transition properties, particularly its advantageous melting behavior, and suitable viscosity profile, LF-polyol was selected for making rigid and flexible polyurethane foams. The same density was targeted for the foams. Rigid foam of density 163 kgm -3 and flexible foam of density 161 kgm -3 were prepared from LF-Polyol (see formulation recipe in Table 4.2) by the same protocol that was used for the preparation of PMTAG Polyol foams [8]. 145

171 4.9.1 FTIR of LF-PMTAG Polyol Foams Figure 4.6 represents the FTIR spectra of the rigid and flexible foams prepared from LF-Polyol. One can first notice that there is no significant difference between the two spectra. The broad absorption bands of NH groups centered at cm -1 and C=O at 1700 cm -1 confirms the presence of urethane linkages [21]. The band centered at cm -1 is characteristic of C-N bonds in the urethane linkage [22]. The band at 2270 cm -1 related to NCO groups indicates that the isocyanates was not fully reacted [21, 23]. The overlapping peaks between 1710 and 1735 cm -1 suggest the presence of urea and isocyanurates in the foams. The peak at cm -1 reveals the presence of isocyanurate trimers, indicating the occurrence trimerization reaction of diisocyanates during the foaming process. The characteristic band related to ester carbonyl (C=O) of the polyol backbone is visible at 1744 cm -1. The stretching vibration of -C-H in -CH3 and -CH2 groups in the aliphatic chains is visible at cm -1 and cm -1, respectively [24]. 146

172 Absorbance 3344 cm cm cm cm cm cm cm cm cm -1 FF RF Wavenumber (cm -1 ) Figure 4.6. Typical FTIR spectra of the rigid (RF) and flexible foams (FF) prepared from LF-Polyol SEM Analysis of LF-Polyol Foams Figures 4.7a and 4.7b shows SEM images of the rigid and flexible foams, respectively. one can notice that the rigid foam displayed more compact and uniform closed cells compared to flexible foam because of the effect of the terminal hydroxyl glycerin cross linker added in the rigid and not in the flexible foam formulation [25]. In the absence of a glycerin cross linker, the terminal and internal hydroxyl groups in the same polyol which cross links at different rates during the polymerization process might be another reason for the non-uniform cell size of the flexible foam [26]. The rigid foam displayed closed cell structure with ~30 cells/mm 2 and a cell size of 217± 24 µm which were higher compared to those of the rigid foams made from PMTAG Polyol (density ~24 cells/mm 2 and cell size 270 ± 40 µm [8]). This is attributable to the high cross linking density promoted by lesser amount of saturated dangling chains in the rigid foams made from the high hydroxyl LF-Polyol compared to the rigid PMTAG Polyol 147

173 foam. The flexible foam displayed a closed cell structure with cell size of ~330 ± 40 µm and cell density (~15 cells/mm 2 ) both smaller than those of the flexible foam made from PMTAG Polyol (cell size ~386 ±55 µm, and density ~18 cells/mm 2 [8]). (a) (b) Figure 4.7. SEM images of rigid and flexible LF-Polyol foams: (a) rigid foam, (b) flexibe foam Thermal degradation Properties of LF-Polyol Foams Figures 4.8 shows the DTG profiles of the rigid and flexible LF-Polyol foams. The corresponding characteristic data are provided in the Appendix listed in Table A8. Both the rigid and flexible foams prepared from LF-Polyol displayed thermal decomposition profile comparable with other vegetable based polyol foams [21, 27, 28]. The DTG curves of the rigid foam and flexible foam showed four prominent peaks (indicated by their peak temperatures in Figures. 4.8) indicating a multi stage decomposition process. The weight loss in the first step of the rigid foam degradation (21%) was higher than in the flexible foam (17%) probably due to the higher amount of short urethane structures from low molecular weight glycerol [29]. The decomposition peak around 300 C involved a total 148

174 weight loss of ~17 to 21 % for the flexible and rigid respectively, and is related to the dissociation of urethane bonds [29, 30]. The decomposition step in the range C is associated with the degradation of the soft segments (polyol backbone) [30]. The soft segments dissociate into carbon monoxide, carbon dioxide, carbonyls (aldehyde, acid, acrolein), olefins and alkenes [18, 30]. This decomposition step involved the largest weight loss with ~65% of the total. More strongly bonded fragments and carbonaceous materials from the previous steps may have decomposed around 450 C [8, 17]. DTG (%/ o C) RF 302 o C 307 o C 361 o C 420 o C 446 o C FF Temperature ( o C) Figure 4.8. (a) DTG of rigid (RF) and flexible (FF) LF-Polyol foams 149

175 4.9.1 Thermal transition Properties of LF-Polyol Foams Heat Flow (Wg -1 ) T g FF RF Temperature ( o C) Figure 4.9. DSC thermogram of rigid (RF) and flexible (FF) LF-Polyol foams Figures 4.9 shows the DSC profiles obtained during the second heating cycle of the rigid and flexible foam from LF-Polyol. The rigid and flexible foams displayed one inflection point indicating a glass transition at ~ C and ~ C, respectively. The glass transitions of the rigid and flexible foams are associated with the molecular motion of the soft segments related to the polyols [31]. Unlike the rigid and flexible foams from PMTAG Polyol [5], those made from LF-Polyol did not show a glass transition related to the relaxation of the urethane segment. This may be due to the compact crosslink network achieved by the foams due to the absence of saturated dangling chains in LF-Polyol Compressive Strength of LF-Polyol Foams The compressive strength versus strain curves of the rigid and flexible foams are shown in Figure 4.10a and 4.10b, respectively. The rigid and flexible foams displayed relatively quick yielding up to 6% and 8%, respectively, followed by a plateau-like region over which there is a little increase in stress with increasing strain. The initial region up to 150

176 ~4% in case of the rigid foam and ~6% in case of flexible foam indicates their respective elastic regions. The plateau-like region resulted from either the collapse or cell wall buckling of the foams [24]. Further compression above 30% (Figure. 4.10b) in case of flexible foams results in crushing of the cell wall and is referred to as the densification region [24]. Compressive strength (MPa) (a) RF Compressive Strength (MPa) (b) FF Strain (%) Strain (%) Figure Compressive strength versus strain curves of (a) Rigid LF-Polyol foam of density 163 kg/m 3 (RF) and (b) Flexible LF-Polyol Foam of density 161 kg/m 3 (FF). Table 4.4. Compressive strength of LF-PMTAG Polyol Foams at different strain (%): Rigid LF-Polyol Foam (RF), Flexible LF-Polyol Foam (FF); Rigid PMTAG Polyol Foam (RF-PMTAG Polyol); and Flexible PMTAG Polyol Foam (FF-PMTAG Polyol) Foams Density (kgm -3 ) Compressive strength Strain (%) 6 10 RF RF-PMTAG Polyol Strain (%) FF FF-PMTAG Polyol

177 The compressive strength of rigid and flexible foams from LF-Polyol at selected strain is presented in Table 4.4. The rigid foam (RF) displayed a higher compressive strength than the rigid PMTAG Polyol foam (1.29 MPa compared to 0.85 MPa at 10%, as seen in Table 4.4). This corroborates that the fractionation process was very effective in removing the saturated chains from LF-PMTAG, leading to LF-Polyol with much less pendant chains, which resulted in a higher compressive strength of the rigid foams. Although LF-Polyol presented a higher OH value than PMTAG Polyol, the flexible foam from LF-Polyol (FF) displayed a lower compressive strength (see Table 4.4) than the flexible PMTAG Polyol foam (FF-PMTAG Polyol) because of the higher percentage of terminal hydroxyls in PMTAG Polyol (~24.1 mol%) compared to the LF-Polyol (~20 mol%) Recovery (%) FF Time (min) Figure Recovery of LF-Polyol Flexible Foam (FF) as a function of time (min) Figure 4.11 shows the percentage of recovery in thickness of flexible foams (FF) as a function of time. The recovery in thickness of the flexible foams were measured after its maximum compression (65%) using a Vernier caliper. The recovery in thickness was 152

178 recorded every minute for the first ten minutes, then after 1, 2, 24 and 48 h. More than 80% recovery was obtained in less than 2 min. Similar like FF-PMTAG Polyol, the FF also showed a good recovery, which substantiates its suitability for flexible foam applications Conclusions The fractionation by dry and solvent mediated crystallization was demonstrated to effectively remove the non-functional saturated triacylglycerols (TAGs) of PMTAG. The fatty acid profile of the fractions of PMTAG was reflected in the chemical characteristics such as iodine value and physical properties such as the thermal phase transitions. The liquid fraction (LF-PMTAG) which was devoid of the saturated TAGs and enriched in unsaturated fatty acid moieties displayed an onset temperature of crystallization 15 C lower than the solid fraction (SF-PMTAG) which retained the trisaturated TAGs and some of the partially unsaturated TAGs. Its onset of crystallization was 11 C lower than that of PMTAG also. However, LF-PMTAG possessed a lower percentage of terminal double bonds compared to PMTAG, probably because these were predominantly found in TAGs with long saturated fatty acid moieties that were selectively filtered with the solid fraction. Also, the molar percentage of oleoyl type molecules, with internal double bonds, was higher in LF-PMTAG compared to PMTAG and SF-PMTAG probably because of its higher content of tri, dioleoyl type of TAGs as well as their combination with short fatty acids moieties. Because the epoxidation and hydroxylation reaction was complete, the polyols synthesized from LF-PMTAG and SF-PMTAG consisted of diols, tetrols and hexols with terminal and internal hydroxyl molecules that matched the composition of the starting fraction. Expectedly, the polyol produced from LF-PMTAG (LF-Polyol) presented an OH 153

179 value (184 mg KOH/g) that is higher than polyol made with SF-PMTAG (SF-Polyol, 136 mg KOH/g ) and PMTAG Polyol (155 mg KOH/g), the polyol synthesized from the nonfractionated PMTAG. LF-Polyol presented a melting point at ~45 C, and a relatively low viscosity when liquid, all characteristics suitable for the processing and transformation of the polyol into polyurethane foams using normal polymerization conditions and existing equipment. The OH value, melting point and viscosity profile of LF-Polyol allowed the preparation of rigid as well as flexible foams having enhanced physical and structural properties. The rigid foam prepared from LF-Polyol for example displayed a compressive strength more than 50% higher than the rigid foam made from PMTAG. Also, the quality of the flexible foam made from LF-Polyol as estimated with the compressive strength and recovery measurements was measurably higher than that of the flexible PMTAG Polyol foam. The closed cell structure of both the rigid and flexible foams, as shown by SEM, indicates that they are suitable for structural and thermal insulation applications. The study demonstrate that the fractionation technology can be used to custom design PMTAG feedstocks with controlled iodine value and varied distribution of unsaturation, position of the double bonds and chain length using existing equipment. It was also demonstrated that polyols with high OH value, and suitable melting and viscosity profiles can be synthesised from such feedstocks, and that enhanced rigid as well flexible polyurethane foams can be easily produced without the need for specialized infrastructure, equipment or technology. 154

180 4.11 References [1] Braipson Danthine S, Gibon V. Comparative analysis of triacylglycerol composition, melting properties and polymorphic behavior of palm oil and fractions. European Journal of Lipid Science and Technology. 2007;109(4): [2] Pawlik H, Prociak A. Influence of palm oil-based polyol on the properties of flexible polyurethane foams. Journal of Polymers and the Environment. 2012;20(2): [3] Narine SS, Kong X, Bouzidi L, Sporns P. Physical properties of polyurethanes produced from polyols from seed oils: II. Foams. Journal of the American Oil Chemists' Society. 2007;84(1): [4] Zlatanić A, Petrović ZS, Dušek K. Structure and Properties of Triolein-Based Polyurethane Networks. Biomacromolecules. 2002;3(5): [5] Prasanth S. Pillai LB, Shaojun Li and Suresh S. Narine. 1-Butene Metathesized Palm Oil & Polyol Derivatives: Structure, Chemical Composition and Physical Properties. Submitted to Industrial Crops and Products [6] Mol J. Catalytic metathesis of unsaturated fatty acid esters and oils. Topics in Catalysis. 2004;27(1-4): [7] Connon SJ, Blechert S. Recent developments in olefin cross metathesis. Angewandte Chemie International Edition. 2003;42(17): [8] Prasanth S. Pillai SL, Laziz Bouzidi and Suresh S. Narine Water-Blown Bio-Based Polyurethane Foams from 1-Butene Metathesized Palm oil Polyol. Submitted to Industrial Crops and Products [9] Hamm W. Trends in edible oil fractionation. Trends in Food Science & Technology. 1995;6(4): [10] Timms RE. Fractional crystallisation- the fat modification process for the 21 st century. European Journal of Lipid science and Technology. 2005;107(1): [11] Dunn RO. Improving the cold flow properties of biodiesel by fractionation: INTECH Open Access Publisher, [12] Kellens M, Gibon V, Hendrix M, De Greyt W. Palm oil fractionation. European Journal of Lipid Science and Technology. 2007;109(4): [13] Ramli M, Siew W, Cheah K. Properties of High Oleic Palm Oils Derived by Fractional Crystallization. Journal of Food Science. 2008;73(3):C140-C5. [14] Hasmadi M, AINI I, Mamot S, Yusof M. The effect of different types of stirrer and fractionation temperatures during fractionation on the yield, characteristics and quality of oleins. Journal of Food Lipids. 2002;9(4):

181 [15] Tan C, Man YC. Differential scanning calorimetric analysis of palm oil, palm oil based products and coconut oil: effects of scanning rate variation. Food Chemistry. 2002;76(1): [16] Zaliha O, Chong C, Cheow C, Norizzah A, Kellens M. Crystallization properties of palm oil by dry fractionation. Food Chemistry. 2004;86(2): [17] Lin B, Yang L, Dai H, Hou Q, Zhang L. Thermal analysis of soybean oil based polyols. Journal of Thermal Analysis and Calorimetry. 2009;95(3): [18] Gryglewicz S, Piechocki W, Gryglewicz G. Preparation of polyol esters based on vegetable and animal fats. Bioresource Technology. 2003;87(1):35-9. [19] Prasanth S. Pillai SL, Laziz Bouzidi and Suresh S. Narine. Solvent Free synthesis of Polyols from 1-Butene Metathesized Palm Oil for Use in Polyurethane Foams. Submiited to Journal of Applied Polymer Science [20] Dai H, Yang L, Lin B, Wang C, Shi G. Synthesis and characterization of the different soy-based polyols by ring opening of epoxidized soybean oil with methanol, 1, 2- ethanediol and 1, 2-propanediol. Journal of the American Oil Chemists' Society. 2009;86(3): [21] Chuayjuljit S, Sangpakdee T, Saravari O. Processing and properties of palm oil-based rigid polyurethane foam. The Journal of The Minerals, Metals & Materials Society. 2007;17:7-23. [22] Piszczyk Ł, Strankowski M, Danowska M, Hejna A, Haponiuk JT. Rigid polyurethane foams from a polyglycerol-based polyol. European Polymer Journal. 2014;57: [23] Narine SS, Yue J, Kong X. Production of polyols from canola oil and their chemical identification and physical properties. Journal of the American Oil Chemists' Society. 2007;84(2): [24] Gu R, Konar S, Sain M. Preparation and characterization of sustainable polyurethane foams from soybean oils. Journal of the American Oil Chemists' Society. 2012;89(11): [25] Szycher M. Handbook of polyurethanes. CardioTech International Inc., Woburn, MA (US); [26] Campanella A, Bonnaillie LM, Wool RP. Polyurethane Foams from Soyoil-Based Polyols. Journal of Applied Polymer Science. 2009;112(4): [27] Ravey M, Pearce EM. Flexible polyurethane foam. I. Thermal decomposition of a polyether based, water blown commercial type of flexible polyurethane foam. Journal of Applied Polymer Science. 1997;63(1):

182 [28] Guo A, Javni I, Petrovic Z. Rigid polyurethane foams based on soybean oil. Journal of Applied Polymer Science. 2000;77(2): [29] Javni I, Petrović ZS, Guo A, Fuller R. Thermal stability of polyurethanes based on vegetable oils. Journal of Applied Polymer Science. 2000;77(8): [30] Shufen L, Zhi J, Kaijun Y, Shuqin Y, Chow W. Studies on the thermal behavior of polyurethanes. Polymer-Plastics Technology and Engineering. 2006;45(1): [31] Tanaka R, Hirose S, Hatakeyama H. Preparation and characterization of polyurethane foams using a palm oil-based polyol. Bioresource technology. 2008;99(9):

183 5 Solvent Free Synthesis of Polyols From 1- Butene Metathesized Palm Oil for Use in Polyurethane foams Introduction Polyurethanes (PU) are versatile polymers which have traditionally been manufactured from petroleum [1]. The range of polyurethane products includes polyurethane elastomers [2], sheets [2], adhesives [3], coatings [4] and foams [2], spanning uses across a large array of industries and products. With a market of $82.6 billion in 2012, PU foams have the largest market share of polymers, projected to reach $131.1 billion by 2018 [5]. PU can be prepared via two principal routes, in the step growth polymerization of isocyanate (NCO) groups and hydroxyl groups [6] and with non-isocyanate pathways, such as the reaction of cyclic carbonates with amines [7], self-polycondensation of hydroxyl-acyl azides or melt transurethane methods [8]. Growing concerns surrounding sustainability, biodegradability, control of CO2 emissions and other environmental problems are driving a search for alternative feedstock to petroleum. Vegetable oils and their derivatives are seen as good renewable materials for the synthesis of polymer substrates, particularly for polyols used in PU production. A 3 Aversion of this chapter is filed as a US provisional patent: 2. U.S. Provisional Patent Application # , (filed January, 2015), Metathesized Triacylglycerol Green Polyols from Palm oil for Use in Polyurethane Applications and Their Related Physical Properties, S.S. Narine, Prasanth. K. S. Pillai, S.Li, and L. Bouzidi and Submitted for a publication in Journal of Applied Polymer Science 158

184 considerable body of work has been already published related to the synthesis of polyols and polyurethanes from a variety of vegetable TAG oils such as soybean oil [9, 10], safflower oil, corn oil, sunflower seed oil, linseed oil [11], rapeseed oil [12], and cotton seed oil [13]. Palm oil presents a particularly interesting potential for industrial use as it is one of the least expensive and most widely available oils (53 million metric ton in 2013: according to the FAO) [14]. However, its high saturated fatty acid composition (50% of the total) and the internal nature of its double bonds limit the potential use of palm oil in PU foam formulations, particularly in rigid PU foams [15]. The internal location of the double bonds results in polyol functionalization with secondary hydroxyl groups, which are less reactive and lead to incomplete crosslinking during polymerization and imperfections in the polymer network [2, 16]. The regions where dangling chains are present do not support stress when the sample is under force, and act as plasticizers, reducing polymer rigidity [17, 18]. Olefin cross metathesis of natural oils and fats is an important organic synthesis technique that is used to produce fine chemicals, substrates and materials, many of which serve as or are potential petrochemical replacements [16, 19-22]. The cross metathesis reaction effectively shortens some of the unsaturated fatty acids of the TAGs at the unsaturated sites, producing terminal double bonds [23, 24], which gives the potential of producing polyols with primary hydroxyl groups, and therefore dramatically reduces dangling chains in polyurethane networks[16, 25]. In addition, the composition of a metathesized product can be controlled by varying the reaction conditions, such as starting 159

185 materials, temperature, type of catalyst, etc. [26-28] allowing for a large range of designer materials. The present work is part of research efforts targeted at investigating the potential of metathesized vegetable oil products for the production of polyols for PU and other polymer applications, and other useful materials. The starting material used in the present study is a 1-butene cross metathesized palm oil (PMTAG) stripped of its olefins, provided by Elevance Renewable Science (ERS). Its full chemical and physical characterization and its conversion into polyols, using solvent-mediated processes, for the preparation of rigid and flexible polyurethane foams have already been reported [29, 30]. Previously, polyols were produced from PMTAG using epoxidation reactions, followed by a hydroxylation method and involved the utilization of harsh and dangerous solvents like DCM and THF. The present effort was targeted at the synthesis of polyols from PMTAG using green, one pot solvent free epoxidation and hydroxylation pathways. The synthesis of green polyols from soybean oil and castor oil by solvent free/catalyst free epoxidation for polyurethane applications was previously reported [31]. The solvent free synthetic route is not only safer and environmentally friendly, but also much more economical. The epoxidation and hydroxylation reaction conditions were tuned to control the conversion of PMTAG double bonds into hydroxyl groups and hence control the hydroxyl value of the polyols. Four batches (B1-4) of these so-called Green Polyols were produced. The chemical structure and composition of the polyols were characterized by 1 HNMR, HPLC, OH value, and Iodine value. Thermal stability, thermal transition behavior, and flow properties were determined by TGA, DSC, and rotational rheometry, respectively. Rigid and a flexible foams were prepared from the Green Polyols with OH values of 83 and 119 mg KOH/ g 160

186 respectively. The foams were characterized by FTIR and SEM. Their thermal stability, thermal transition behavior, and compressive strength were investigated using TGA, DSC, and a texture analyzer, respectively. 5.2 Materials and Methods Materials PMTAG was provided by Elevance Renewable Sciences (ERS, Bolingbrook, II). Formic acid (88 wt %), Iodine monochloride (95%), potassium iodide (99%), phenolphthalein, hydrogen peroxide solution (30 wt%), Dibutin Dilaurate (DBTDL) and glycerin (99.5 %) were purchased from Sigma-Aldrich, Canada (Oakville, Ontario, Canada). Perchloric acid (70%) and N, N-Dimethylethanolamine (DMEA were purchased from Fisher Scientific, Canada. Ethanol (anhydrous), toluene, potassium hydroxide, and sodium thiosulfate were purchased from ACP chemical Inc. (Montreal, Quebec, Canada). All of the above compounds were used as received. Diphenylmethane diisocynate (MDI) from Bayer Materials Science (Pittsburgh, PA), Polyether-modified surfactant (TEGOSTAB B-8404) from Goldschmidt Chemical Canada. The properties of the MDI are presented in Table A10 in the Appendix Chemistry Characterization Titrimetric Methods (OH value, Acid value, Iodine value) OH and acid values of the PMTAG Polyol were determined according to ASTM S and ASTM D , respectively. Iodine value was determined according to ASTM D

187 Proton Nuclear Magnetic Resonance Spectroscopy ( 1 HNMR) 1 H-NMR spectra were recorded in CDCl3 on a Varian Unity-INOVA at MHz. All spectra were obtained using an 8.6 μs pulse with 4 transients collected in points. Datasets were zero-filled to points, and a line broadening of 0.4 Hz was applied prior to Fourier transformation. The spectra were processed using spinwork NMR Processor, version 3. 1 H chemical shifts are internally referenced to CDCl3 (7.26 ppm) Gel Permeation Chromatography (GPC) Molecular weights and distribution were determined by gel permeation chromatography (GPC). The measurements were carried out on an e2695 GPC instrument equipped with a Waters e2695 pump, Waters 2414 refractive index detector and a 5-µm Styragel HR5E column (Waters Alliance, Milford, MA). Chloroform was used as eluent with a flow rate of 0.5 ml/min. The concentration of sample was 1 mg/ml and the injection volume was 10 µl. Polystyrene (PS) standards and pure TAG-oligomers (synthesized previously [32]) were used for calibration. Waters Empower Version 2 software was used for data collection and data analysis Fourier Transform Infrared Spectroscopy (FTIR) The FTIR spectra of the foams were obtained with a Thermo Scientific Nicolet 380 FTIR spectrometer (Thermo Electron Scientific Instruments, LLC, USA) equipped with a PIKE MIRacle TM attenuated total reflectance (ATR) system (PIKE Technologies, Madison, WI, USA.). Solid samples were loaded onto the ATR crystal area, and sample spectra were acquired over a scanning range of cm -1 for 32 repeated scans at a spectral resolution of 4 cm

188 5.2.3 Physical Characterization Techniques Thermogravimetric analysis (TGA) TGA measurements were carried out on a TGA Q500 (TA Instruments, DE, USA) equipped with a TGA heat exchanger (P/N ). Approximately mg of sample was loaded into the open TGA platinum pan. The sample was heated at a constant rate of 10 C/min from 25 to 600 C under dry nitrogen. The TA Universal Analysis software (TA Instruments, New Castle, DE) was used to analyze the TGA curves Differential Scanning Calorimetry (DSC) DSC measurements were performed on a Q200 model (TA Instruments, New Castle, DE) under a nitrogen flow of 50 ml/min. Polyol samples between 3.5 and 6.5 (± 0.1) mg were run in standard mode in hermetically sealed aluminum pans. The sample was equilibrated at 90 C for 10 min to erase thermal memory, and then cooled at 5.0 C/min to -90 C where it was held isothermally for 5 min and subsequently reheated at a 5.0 C/min to 90 C. Foam samples between 3.0 and 6.0 (± 0.1) mg were run in modulated mode in hermetically sealed aluminum DSC pans. The sample was first equilibrated at 25 C and heated to 150 C at 10 C/min (first heating cycle). The sample was held at that temperature for 10 min and then cooled to -90 C at 10 C/min, where it is held isothermally for 5 min and subsequently reheated to 150 C at the same rate (second heating cycle). The modulation amplitude and period were ±1 C and 60 s, respectively. 163

189 The TA Universal Analysis software was used to analyze the DSC thermograms. The characteristics of non-resolved peaks were obtained using the first and second derivatives of the differential heat flow Rheology The flow behavior and viscosity versus temperature of the polyols were measured on a temperature controlled Rheometer (AR2000ex) using a 40-mm, 2 steel geometry. Temperature control was achieved by a Peltier attachment with an accuracy of ~0.1 C. Shear stress versus shear rate curves were measured at 10 C intervals from high temperature (100 C) to ~ 10 C below the DSC onset of crystallization temperature. The viscosity versus temperature data were collected at constant shear rate (200 s -1 ) using the ramp procedure while the sample was cooling (1.0 and 3.0 C/min) from ~110 C to just above the crystallization point. Data points were collected at 1 C intervals. The shear rate shear stress curves were fitted with the Herschel-Bulkley equation (Eq. 5.1), a model commonly used to describe the general flow behavior of liquid materials, including those characterized by a yield stress. n 0 K Eq. 5.1 Where denotes the shear stress, 0 is the yield stress below which there is no flow, K the consistency index and n the power index. n depends on constitutive properties of the material. For Newtonian fluids n = 1, and for shear thickening and shear thinning fluids n 1 and n 1, respectively. 164

190 Texture Analysis The compressive strength of the foams were measured at room temperature using a texture analyzer (TA-TX HD, Texture Technologies Corp, NJ, USA). Samples were prepared in cylindrical Teflon molds 60-mm in diameter and 36-mm in length. During compressive force measurements, the cross head speed was 3.54 mm/min, recorded on a 750 Kgf load cell for both the rigid and flexible foams. The load was applied until the foam was compressed to approximately 15% and 65% of the original thickness of the rigid and flexible foams, respectively Scanning Electron Microscopy (SEM) Composite SEM images of the foams were resolved with a Phenom ProX, (Phenom- World, The Netherlands) scanning electron microscope at an accelerating voltage of 15 kv and map intensity. Uncoated foams were cut into thin rectangular segments and fixed to a temperature controlled sample holder with conductive tape. Samples were cooled to -25 C to prevent beam induced thermal deformations, and composite images were captured using the Automated Image Mapping software (Phenom-World, The Netherlands) Synthesis Methods Epoxidation 2 kg PMTAG was added into 2 kg formic acid (88%) in a 20L reactor fitted with a HAAKE Phoenix II temperature controlled circulator (Thermoscientific, Newington, NH). The initial reaction temperature of the epoxidation was varied ( T in Table 5.1) depending on the batch. 2.8 L of hydrogen peroxide (30%) was added to the reactor slowly (~1 L/h) while the reaction mixture was vigorously stirred. During addition of hydrogen Epx ini 165

191 peroxide, the exothermic nature of the epoxidation reaction caused the temperature to increase. In the case of Batch 3, the temperature controlled system wasn t used, the temperature of the reaction reached a maximum of 95 ºC but remained less than 10 min at that temperature. Due to the exothermic nature of the epoxidation reaction, the temperature Epx of the other batches also increased ( T max in Table 5.1). Tap water was circulated to cool Batch 4, and the control feature of the circulator was used to bring Batch 1 and Batch 2 to the actual epoxidation temperature ( T in Table 5.1). The epoxidation reaction was continued at Epx R Epx T R overnight. The reaction mixture was finally washed with 2 1 L water, 1 1 L 5% NaHCO3 and 2 1 L water sequentially. The mixture was used for the next step directly. Yield > 95 %. polyols. Table 5.1. Epoxidation reaction temperature and time data for the synthesis of green Epx T ini Epx : Initial temperature of the epoxidation reaction; T max : highest temperature reached during the epoxidation reaction; : reaction time Epx T R : reaction temperature for epoxidation; Epx t R Batch Epoxidation Epx Epx T ini T max Epx T R Epx t R h at 45 ºC then 12 h at 48 ºC h at 48 ºC h at 45 ºC h at ºC 166

192 Hydroxylation The epoxide of PMTAG (2 kg) above was added into 10 L water, and then followed by 140 g HClO4 (70%) with a ratio of PMTAG/H2O/perchloric acid = 1/5/0.05. The reaction mixture was heated to ~ 85 C and stirred at that temperature for 16 h after which stirring and heat were ceased and the mixture sat at room temperature to aid in separation. The organic layer was washed with 2 1 L water, 1 1 L 5% NaHCO3 and 2 1 L water sequentially, and then dried on a rotary evaporator. Yield > 95 % Polymerization Method Rigid and flexible polyurethane foams were prepared from B3- and B4-Green polyol and MDI using a previously published method. The formulation recipes for the rigid and flexible foams are presented in Table 5.2. The amount of each component was based on 100 polyol parts by weight. As shown in Table 5.2, the rigid foams were prepared based on a total hydroxyl value of 450 mg KOH/g. In The case of the rigid foams, glycerin, a poly hydroxyl cross linker, was added into the reaction mixture (20.1 and 18.1 parts for B3- and B4-Polyol Rigid Foams, respectively) in order to obtain the targeted hydroxyl value of 450 mg KOH/g (see Table 5.2). The amount of MDI in both rigid and flexible foam formulations was adjusted to achieve an isocyanate index of 1.2 (NCO to OH ratio of 1.2 to 1). Note that the NCO to OH ratio in the rigid foam formulation includes the OH from the added glycerol. The amount of cross linking catalyst DBTDL, which favors the gelling reaction, and the co-catalyst DMEA, which functions as a blowing catalyst, were fixed at 1 and 0.5 parts 167

193 respectively based on the fairly good compressive strength previously obtained for rigid polyurethane foams prepared from terminal hydroxyl polyols. The cross linking catalyst DBTDL, which favors the gelling reaction, and the cocatalyst DMEA, which functions as a blowing catalyst, were used for the polymerization process. The choice of the catalyst ratios were fixed based on the fairly good compressive strength previously obtained for rigid polyurethane foams prepared from terminal hydroxyl polyols. Table 5.2. Formulation Recipes for Rigid and Flexible Foams. Amounts are based on 100 parts by weight of total polyol Rigid Foams Flexible Foams Ingredient Parts Parts B3-Green Polyol or B4-Green Polyol OH: NCO ratio 1:1.2 1:1.2 Glycerin B B Water 2 2 Surfactant 2 2 Catalyst Co-catalyst All the ingredients except MDI were melt and weighed into a beaker and mixed for s. The pre-measured MDI was then added into the beaker and stirred vigorously for 5 to 20 s and transferred into a cylindrical Teflon mold (60 mm diameter and 35 mm long) which was previously greased with silicone release agent. The mold was then then sealed with a hand tightened clamp and the sample was cured for four days at 40 ºC, with an 168

194 additional post curing of one day at room temperature. Table 5.2 gives the formulation recipe used for the preparation of rigid and flexible polyurethane foams from B3- and B4- Green Polyols. 5.3 Results and Discussion Solvent Free Synthesis of Polyol from PMTAG The Green Polyols were prepared from PMTAG in a solvent-free one-pot two-step reaction; epoxidation by formic acid and hydrogen peroxide (H2O2), followed by hydroxylation using perchloric acid (HClO4) as the catalyst, as described in Scheme 5.1. The formic acid (88%)/H2O2 (30%)/PMTAG ratio was kept at 1/1.4/1 and PMTAG/H2O/perchloric acid at 1/5/0.05 in all the batches. The epoxidation conditions (temperature and time) were adjusted in order to optimize the reaction, control the OH value, and to manage the amount of formic acid that can become attached to the polyol. The temperature and time of the four different batches of epoxidation reactions were tuned so as to control the conversion of the double bonds into epoxides (see Table 5.1). The controlled double bond conversion subsequently enables the production of polyols with controlled hydroxyl value. Note that when the temperature was below 70 ºC, the degree of epoxidation in the melt was limited (~80 to 90 % conversion of total double bonds). Also, at temperatures higher than 50 C, the epoxide was opened by formic acid and formic acid units were found attached to some of the polyol backbones. Therefore, in order to avoid formic acid units attached to the polyol backbone, the epoxidation temperature should be kept below 50 ºC. The hydroxylation of all the batches was run at 85 C over 16 h. The Green Polyols obtained from the four batches are labelled B1 B4-Polyol. 169

195 Scheme 5.1. Solvent-free synthesis of polyols from PMTAG. n= 0, 2, 8; m= 11 to Chemical Characterization and Compositional Analysis of PMTAG Green Polyols The structure of the epoxides was confirmed by 1 H-NMR. The characteristic chemical shift values of the specific protons of B1-, B2-, B3- and B4-epoxy PMTAG are provided in Appendix in Table A11. The chemical shift at 2.85 ppm, related to the nonterminal epoxy ring, and the chemical shift at 2.7 to 2.4 ppm related to the terminal epoxy ring appeared for the epoxidized PMTAG of all the batches, indicating that the epoxidation 170

196 reaction was successful. However, although the chemical shift at 5.4 ppm related to internal double bonds disappeared, peaks at 5.0 to 4.8 ppm were still present, indicating that the terminal double bonds were not completely converted into epoxides. The relative amount of remaining terminal double bonds (RTDB) as estimated by 1 H-NMR for each batch of epoxy PMTAG is provided in Table 5.3. Note that RTDB (mol%) was calculated as the ratio of remaining terminal double-bonds in the PMTAG epoxide to the terminal double bonds in the starting PMTAG material. The chemical shift at δ 8 ppm indicating the presence of formic acid attached to the backbone of the epoxide was present in the epoxidized PMTAG of B1 and B2 but not B3 and B4. The number of formic acid units per TAG epoxide, as estimated by 1 H-NMR, is provided in Table 5.3. The structure of the Green Polyols (B1 to B4) were confirmed by 1 H-NMR. Figures A11 in the Appendix show the 1 H-NMR spectra of B1-B4 Green Polyols, respectively. The corresponding 1 H-NMR chemical shifts in CDCl3 are listed in Table A12. The spectra of all the polyols presented the chemical shift related to protons neighbored by OH (at ppm) but not the chemical shift related to epoxy rings (at ppm) indicating that the hydroxylation reaction was complete. The Green Polyols presented the typical chemical shift related to a glycerol skeleton: -CH2CH(O)CH2- at δ ppm, - OCH2CH(O)CH2O- at ppm, -C(=O)CH2- at δ ppm, and -C(=O)CH2CH2- at δ 1.60 ppm. The peak areas of chemical shifts at ppm and at 4.2 to 4.0 ppm were equal, indicating that hydrolysis of the TAGs was avoided. Because the epoxidation of the terminal double bonds was not complete, the Green Polyols also showed chemical shifts of the remaining terminal double bonds (-CH=CH2 at 5.8 ppm, and CH=CH2 at ppm). The formic acid units on the backbone (chemical shift at δ 8 ppm) were presented 171

197 in B1- and B2-Polyols but not in B3- and B4-Polyols, similar to their starting epoxides. The RTDB (mol%) of the Green Polyols and the number of formic acid units per TAG polyol are listed in Table 5.3. Table 5.3. Amount of remaining terminal double bonds (RTDB) 1, number of formic acid units per TAG polyol and terminal OH groups as estimated by 1 H-NMR. Iodine value, Acid value and OH number of PMTAG Green Polyols. Green PMTAG Epoxides Green Polyols Formic RTDB Terminal Iodine OH Value Acid Value Batch acid (mol%) OH group Value (mg (mg RTDB units (mol%) KOH/g) KOH/g) (mol%) per TAG B B B B Remaining terminal double bonds (RTDB%) was calculated as the ratio of remaining terminal double-bonded fatty acids in Green Polyol to the terminal double bonded fatty acids in PMTAG The solvent free synthetic strategy adapted (see section 2.5) was very successful for the synthesis of Green Polyols with controlled OH values. It was also confirmed in the 1 HNMR characterization of the epoxides and polyols that the controlled reaction parameters such as Epx T ini and Epx T R (see Table 5.1) facilitated the avoidance of formic acid units attached on the epoxide backbone in batches B3 and B4. Also the polyols produced from the resultant epoxides such as B3-Green Polyol and B4-Green Polyol were completely 172

198 free from formic acid residuals. The Green Polyols presented OH values between 83 to 119 mg KOH/g (Table 5.3) and very low acid values, except for B1-Green Polyol which displayed a relatively high acid value due to its longer epoxidation reaction time. Although the OH values achieved using the green route are relatively lower compared to those of the PMTAG Polyols prepared previously with solvents [29], they are large enough to make suitable monomers for the preparation of flexible as well as rigid foams. B3- and B4- Green Polyols which displayed very low acid values, no formic acid attached and significantly different OH values (83 and 119 mg KOH/g respectively) were chosen for further physical characterizations, and used for the preparation of rigid and flexible polyurethane foams. The GPC of the B3- and B4-Green Polyols (the GPC data are provided in the Appendix in Figure A12 and Table A13) revealed the presence of relatively important levels of oligomers in the polyols. These include high molecular weight (Mw: 7030 g/mol) oligomers as well as low molecular weight (Mw: 1463 g/mol) oligomers. B3- and B4- Green Polyols comprised 45% and 37% oligomers, respectively, compared to 13% oligomers in PMTAG Polyol. The higher oligomerization during the solvent free reaction was due to its higher reaction temperature [33]. The composition of the PMTAG Green Polyols was determined with the help of 1 H- NMR and HPLC analyses of the column chromatographic fractions of B4-Polyol. Seven different fractions (labelled F1 to F7) were obtained with ethyl acetate and hexanes as the solvents. Column chromatography, 1 H-NMR and HPLC data are provided in in the Appendix in Table A

199 Scheme 5.2. General structures in PMTAG Green Polyol (n= 0, 2, 8; m= 11 to 20) The 1 HNMR of F1 did not present the chemical shift at ppm which is related to OH groups indicating that it is not the hydroxyl derivative. Also, F1 presented ~ 24 mol% unreacted terminal double bonds. F2 and F3 presented hydrolyzed TAG structures formed during the hydroxylation reaction. The 1 HNMR of F4, F5 and F6 presented chemical shifts at δ ppm and ppm of -CH2CH(O)CH2- and - OCH2CH(O)CH2O- of the glycerol skeleton, respectively, and at δ ppm of the proton neighboring hydroxyl groups indicating the presence of TAG diols and TAG tetrols. F4, F5 and F6 presented also some unreacted terminal double bonds (~10 mol%) as revealed by the chemical shifts at ppm. Fraction F7 presented only tetrols (as revealed by the chemical shift at δ ppm, with ~ 15 mol% unreacted terminal double bonds. 174

200 The 1 HNMR results were confirmed and complemented by HPLC. The general structures of the green polyols resulting from these analyses and based on structures of PMTAG itself [29] are presented in Scheme Physical Properties of PMTAG Green Polyols Thermogravimetric Analysis of Green PMTAG Polyols As indicated by the DTG profiles of B3- and B4-Green Polyols shown in Figure 5.1, B3- and B4-Green Polyols presented similar traces indicating a two-step degradation process. The large DTG peak at ~380 ºC (TD1 in Figure 5.1) is associated with the breakage of the ester bonds [34]. This dominant step which was initiated at 240 C and concluded at ~ -420 C involved ~ 60% of weight loss. The small DTG shoulder peak at ~ 450 C (TD2, in Figure 5.1) is related to the decomposition of the ester groups and other fragments, and the degradation of the remaining carbonaceous materials from the previous step [35]. The onset of degradation of B3- and B4-Green Polyols as determined at 10% d weight loss ( T 10% ) was higher than 310 ºC, indicating a good thermal degradation stability d for the Green Polyols, comparable to other vegetable based polyols. Note that T 10% of B4-Green Polyol was relatively smaller compared to B3-Green Polyol (12 ºC lower) probably due to the loss of terminal hydroxyls which content is higher in B4-Green Polyol [35]. 175

201 2.0 TD1 DTG (% o C -1 ) TD Temperature ( o C) B3 B4 Figure 5.1. DTG profiles of B3- and B4-Green Polyols Crystallization and Melting Behavior of PMTAG Green Polyols The crystallization and heating profiles (both at 5 C/min) of B3- and B4-Green Polyols are shown in Figure 5.2a and 5.2b, respectively. The corresponding thermal data is listed in the Appendix in Table A15. as can be seen in Figure 5.2, B3- and B4-Green Polyols present similar crystallization and heating behaviors with marked separation of a high and low temperature events inherited from the PMTAG similarly to the PMTAG Polyol synthesized via solvent mediation [29]. The difference between B3- and B4- Green Polyol manifested in a small difference in their onset temperature of crystallization (26 C and 29 C, respectively) and offset temperature of melting (48 C and 50 C, respectively). Note that these values are consistent with the fact that B3-and B4-Green Polyols were not liquid at ambient temperature. The large difference in their OH values was not reflected in either the crystallization or melting traces, indicating that other structural attributes such as remaining double bonds and short chain moieties played a counter effect. The melting point of the Green Polyols as determined by the offset temperature of melting is ~2 ºC higher 176

202 than what was measured for the PMTAG Polyol synthesized via solvent mediation [29]. This may be due to the higher percentage of oligomers in the Green Polyols. (a) 0.0 (b) Heat Flow /Wg -1 (Exo up) B4 B3 P2 P Temperature ( o C) Heat Flow /Wg -1 (Endo down) B4 B3 G2 G Temperature ( o C) Figure 5.2. DSC thermograms of B3-, and B4-Green Polyols obtained during (a) Cooling, and (b) subsequent heating (5 C/min). The heating thermogram of the Green Polyols displayed two groups of endothermic events (G2 below 30 C, and G1 above 30 C in Figure. 5.2b) corresponding to the melting of a high and low melting portions of the polyols. the enthalpy of melting of G1 and G2 (~26 J/g and ~66 J/g, respectively) was very similar to the enthalpy of P1 and P2, respectively, suggesting that they are effectively the recording of the melting of the high and low melting portions of the polyol, respectively. These DSC data indicate that with careful processing, it is possible to separate PMTAG Polyol into two fractions: one mainly constituted of low melting components, and another mainly constituted of high melting components. It is expected that at ambient temperature, one fraction will be solid and the other will remain liquid. 177

203 Flow Behavior and Viscosity of B3-and B4- Green Polyols Selected shear stress versus shear rate curves recorded for B3-, B4-Green Polyols at selected temperatures are shown in Figures. 5.3a and 5.3b respectively. Fits to the Herschel-Bulkley model (Eq. 5.1) are included in the figures (dashed lines in Figures. 5.3a and 5.3b). Evident from Figure. 5.3, shear rate shear stress curves were linear for the entire range at temperatures from 40 C to 90 C for B3-Green Polyol and at temperatures from 50 ºC to 90 ºC for B4-Green Polyol indicating Newtonian behavior. Application of Eq. 5.1 to the share rate shear stress data generated power index values ( n ) close to unity and no yield stress (straight lines in Figure. 5.3, R 2 > ). The deviation from the Newtonian behavior above 200 s -1 at 30 C for B3-Green Polyol and above 400 s -1 at 40 C for B4-Green Polyol is due to the close proximity to the onset temperature of crystallization. Since their onsets of crystallization are closer than the temperatures at which their flow was Newtonian, the difference in flow behavior between B3-and B4- Green Polyols is attributed to the difference in OH value and terminal hydroxyls content which were higher in B4-Green Polyol. The viscosity versus temperature curves of B3- and B4-Green Polyols (Figure. 5.4) presented the typical exponential behavior of liquid hydrocarbons [36, 37]. The viscosity of the B4- Green Polyol was higher than that of B3-Green Polyol at all temperatures due to a higher number of hydroxyl groups which increases the polarity and intermolecular attractive force between the molecules by hydrogen bonding [38]. 178

204 Figure 5.3. Shear rate- shear stress of PMTAG Green Polyols. (a) B3-Green Polyol (b) B4-Green Polyol, respectively. 0.8 B3 B4 Viscosity (Pa.s) Temperature ( o C) Figure 5.4. Viscosity versus temperature curves obtained during cooling (1 C/min) of B3-Green Polyol (empty circles) and B4-Green Polyol (empty triangles). Dashed lines are guides for the eye. The Green Polyols presented a slightly higher viscosity compared to the PMTAG Polyol prepared using solvents [29]. This is explained by the presence of more oligomers in the B3- and B4-Green Polyols (37 and 45 %, respectively compared to 13% in PMTAG 179

205 Polyol) formed during their hydroxylation step at 85 C. The viscosities of the Green Polyols are close to the range of viscosities of other polyols prepared from highly unsaturated vegetable oils that are currently used in polyurethane applications [33, 39-41] Polyurethane Foams One rigid and one flexible foam were prepared from B3- and B4-Green Polyols using a previously reported polymerization method [30]. As can be seen in Figure 5.5, the polyurethane foams presented a smooth surface and a light yellow color. Note that the catalyst amount for flexible foam formulation was fixed (0.5 parts, see Table 5.2), chosen to avoid the cracks observed during the compression of the flexible foams made with smaller catalyst concentrations. (a) B3-RF145 (b) B3-FF162 (c) B4-RF166 (d) B4-FF156 Figure 5.5: Pictures of rigid and flexible foams from B3-and B4-Green PMTAG Polyols. (a) B3-Green Polyol rigid foam of density 145 kgm -3 (B3-RF145), (b) B3-Green Polyol flexible foam of density 162 kgm -3 (B3-FF162), (c) B4-Green Polyol rigid foam of density 166 kgm -3 (B4-RF166).and (d) B4-Green Polyol flexible foam of density 156 kgm -3 (B4- FF156) FTIR of B4-Green Polyol Foams The FTIR spectra of the rigid and flexible foams produced from both B3- and B4- Green Polyol confirmed the formation of urethane linkages. As shown in Figure 5.6, 180

206 representing the FTIR spectra of B4-flexible and a rigid foams typical of all the foams, the characteristic absorption band of NH groups, C=O and C-N bonds which are associated with the urethane linkage were presented at cm -1, 1700 cm -1 and at 1516 cm -1, respectively, (Figure 5.6) [42, 43]. However, as indicated by the weak band at 2270 cm -1 of the NCO group, some of the isocyanate did not react with the polyol [17, 42]. The overlapping peaks between 1710 and 1735 cm -1 suggest the presence of urea and isocyanurates in the foams. The peak at ~ cm -1 reveals the presence of isocyanurate trimers, indicating the occurrence of trimerization reactions of the diisocyanates during the foaming process. The stretching bands of the ester groups are particularly visible at 1744 cm -1 (C=O), cm -1 (O-C-C) and cm -1 (C- C(=O)-O). The stretching vibration of -C-H in -CH3 and -CH2 groups in the aliphatic chains are also visible at cm -1, and 2850 cm -1 respectively [44]. The CH2 stretching vibration and CH2 bend are also clearly visible at cm -1 and cm -1, respectively [17]. Absorbance cm cm cm cm cm cm cm -1 RF FF Wavenumber (cm -1 ) 800 Figure 5.6. Typical FTIR spectra of rigid (RF) and flexible (FF) B4-Green Polyol foam. 181

207 SEM Analysis of Green Polyol Foams Figures 5.7a, 5.7b and 5.7c, 5.7d show SEM images of the rigid and flexible foams prepared from B4- and B3-Green Polyol, respectively. The cell structures of Figures 6a-d are typical of all the rigid and flexible foams prepared in the present work. The characteristics of the cell structure such as number and size of the cells was determined from the analysis of all the visually separate cells of at least two specimens of each foam. The values provided here are the subsequent calculated average and standard deviations. The Green Polyol rigid foam displayed compact and uniformly distributed cells (B4: 450 ± 44 µm, B3: 475± 60 µm). On the other hand, although with a somewhat similar average cell size (B4: 494±145 µm, B3: 500 ±190 µm) the Green Polyol flexible foam presented a heterogeneous cell structure with cell size ranging from 277 µm to 784 µm for B4 and 200 µm to 800 µm for B3. The stark differences in cell structure between the rigid and flexible foams is attributable to the compounded effects of high cross linking density achieved by the addition of glycerin in the rigid foam formulation and the different rates of crosslinking of terminal and internal hydroxyls in the Green polyol flexible foam formulation [45]. Since both rigid and flexible foams only contain closed cells, they may also have applicability in thermos insulation applications. Both the rigid and flexible foams prepared from the PMTAG Green Polyols displayed a smaller number of cells and larger cell size than the rigid and flexible foams from PMTAG Polyol prepared via solvent mediation [30]. Beside the OH value and terminal OH group effects considerations (OH value 119 mg KOH/g and 18.3% terminal hydroxyl in the B4-Green Polyol for example vs. OH value of 155 mg KOH/g and 24.1% terminal hydroxyl groups in the polyol prepared via solvent mediation), the larger amount 182

208 of oligomers in the Green Polyol (37% in B4-Green Polyol) may have added an extra contribution for the larger size of cells of the rigid and flexible Green Polyol foams. (a) (b) (c) (d) Figure 5.7. SEM micrographs of (a) B4-Green Polyol rigid foam, (b) B4-Green Polyol flexible foam, (c) B3-Green Polyol rigid foam and (d) B3-Green Polyol flexible foam 183