Carboxylated and Thermal Stable CNC and CNF with Tailored Morpholgies Produced Using Fully Recyclable Solid Di-carboxylic Acids

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1 Carboxylated and Thermal Stable CNC and CNF with Tailored Morpholgies Produced Using Fully Recyclable Solid Di-carboxylic Acids J.Y. Zhu Fulbright-Aalto Distinguished Chair, Aalto University, Finland US Forest Service, Forest Products Laboratory, Madison, WI Grenoble, France June 13-16, 2016

2 Cellulose Nanocrystals (CNC) Concentrated acid hydrolysis sulfuric acid Low yield < 50% Recovery of acid Thermal stability 9 kg acid/kg CNC 13 kg Sulfate/kg CNC

3 Cellulose Nanofibrils (CNF) Mechanical Fibrillation Microfibrils Lack of Functionality, Dispersion Oxidation and other Chemical TEMPO mediated oxidation Recovery of chemical and high cost Low thermal stability, large water usage

4 Cellulose Nanofibrils (CNF) Enzymatic + Mechanical Functionality, Dispersion Energy cost 1. Thermal Stability 2. Functionality/dispersion 3. Chemical Recovery/Sustainability 4. Cost / Forest management

5 Production of Cellulose Nanocrystals (CNC) Elementary fibril Rowland and Roberts J Polym Sci Part A-1 Polym Chem 10: Busse-Wicher et al. (2014), The Plant J. 79:

6 Why Solid Acids Acid can effectively fractionate hemicelluloses Acid can also depolymerize cellulose Solid acid can be easily recovered Di-carboxylic acid of potential functionalization Substantial interest in using solid acids Di-Carboxylic acid cam esterify cellulose result in carboxylation

7 Effects of Acid Concentration Chen et al., Cellulose, 22: , Maximal CNC yield exp (%) L 21 = 228 S = 6.0 CrI = 75.5 L 21 = 174 S = 7.6 CrI = 76 L 21 = 131 S = 6.8 CrI = Sulfuric acid concentration (wt%)

8 Dicarboxylic Acid (DCA) Hydrolysis: Esterification and Carboxylation Oxalic acid Carboxylation + H 2 O Maleic acid

9 Experimental

10 Acid C (wt%) T ( C) Typical Yield Results t (min) FCSR yield (%) CNC yield (%) Reducing sugar recovery (%) Xylose recovery (%) Glucose recovery (%) O ±0.4 ND ± ± ± ± ± ± ± ± ± ± ± ± ±0.3 12± ± ± ± ± ± ± ± ± ± ± ±0.3 12± M ± ±0.0 ND ± ±0.0 ND ± ±0.0 ND ± ±0.0 ND ± ±0.0 ND

11 DCA-CNC: Morphology 13.4 Aspect Ratio: Scale = 5 µm Scale = 500 nm

12 DCA - Esterification Absorption (%) Transmittance Wavenumber (cm -1 ) BEP (O70,100, 60) (M60, 100, 45) Wavenumber (cm -1 )

13 CNC Sample DCA Carboxylation, Charge, CrI NMR relaxation time T2 (ms) CNC Charge (mv) COOH (mmol/g CNC) CrI (%) BEP ND 76.0 ± 0.4 (O50, 100, 45) ± (O60, 100, 45) ± (O70, 100, 45) ± (O50, 100, 90) ± (O60, 100, 90) ± (O70, 100, 60) ± (M50, 100, 45) ± 0.4 (M60, 100, 45) ± 0.2 (M70, 100, 45) ± 0.7 (S64, 45, 45) ± ± 0.2 (PA, 67,45) ± 0.6 (H14, 100, 45) ± 0.7

14 DCA-CNC: Thermal Stability Weight (%) dw/dt (%/ o C) BEP (O70,100, 60) (M60,100,45) (T50,100,45) (B50,100,45) (P67,100,45) (S64,45,45) (H14,100,45) a Hydrolysis conditions Onset degradation T onset ( o C) CNC Weight loss at T onset (%) T 95 at 5% weight loss ( o C) CNF Onset degrad. T onset ( o C) (O70, 100, 60) (M60,100, 45) (T50, 100, 45) (B50, 100, 45) BEP (P67, 100, 45) Temperature ( o C) b (S64, 45, 45) (H14, 100,45)

15 DCA-CNC: Thermal Stability Oven Heating for 4 and 24 h at 105 o C 4 h Sulfuric acid CNC (S64, 45, 60) Oxalic acid CNC (O70, 100, 60) 24 h

16 DCA Recovery: Crystallization

17 DCA-CNF: Morphology (O50, 100, 45) Aspect Ratio: ~120 ~ µm 1 µm 1 µm A (O50, 100, 45) B (O60, 100, 45) C (O70, 100, 45)

18 DCA Carboxylation, Charge, DP CNC Sample CNF Charge (mv) CNF COOH (mmol/g) CNC Charge (mv) CNC COOH (mmol/g) BEP (O50, 100, 45) ± ± (O60, 100, 45) ± ± (O70, 100, 45) ± ± (O50, 100, 90) ± ± (O60, 100, 90) ± ± (O70, 100, 60) ± ± (S64, 45, 45) ± 0.8 (PA, 67,45) ± 0.6 (H14, 100, 45) ± 0.7 (O50, 100, 45) : 287 ND (O60, 100, 45) : 265 DP of FCSR : 18 (O70, 100, 45) : 239

19 Aqueous (O50, 100, 45) Aqueous (O50, 100, 45) Enhancing Esterification and Carboxylation: Catalyst and Solvent Effect System Catalyst or Solvent COOH (mmol/g) None 0.11 H 2 SO 4: 0.2 mol/l 0.38 p-toluenesulfonic acid: 0.2 mol/l 0.32 Solvent (O30/A70, 100, 60) Acetic acid: 70wt% 0.63 Solvent (M40/MAH20/A40, ) Acetic acid: 40wt% Maleic anhydride (MAH): 20wt% 1.51 (O50, 100, 60) = Oxalic acid 50wt% at 100 o C for 60 min

20 Using Combined Hydrolysis Factor (CHF) Control DP and CNF Morphology (M55, 100, 60) FCSR DP = DP E CHF (min.mol/l) (M75, 120, 120) FCSR DP = 206 Scale Bar = 1 µm 20

21 Summary Highly thermal stable CNC + CNC Carboxylated (Charged) CNC + CNF Easily scalable production process Fully and commercially proven recyclable chemicals Tunable of CNC and CNF properties Tunable productivity of CNC vs CNF Potential low cost

22 DCA-CNC: Diameter distribution Probability density (1/nm) (O50, 100, 45) (O60, 100, 45) (O70, 100, 45) (O50, 100, 90) Crystal height (nm)

23 Probability density (1/nm) Extent of Fibrillation: Diameter Distribution Passes Fibril height (nm)

24 Future Work Production from wood chips directly or unbleached fibers Property optimization Scale-up Economic analyses Looking for partnership and applications for CNC/CNF composites

25 2000 DCA-CNC: NMR Water Interaction t2 (ms) 1400 (O50, 100, 90) (O70, 100, 60) (O50, 100, 45) (O60, 100, 45) (O70, 100, 45) (H14, 100, 45) (P67, 100, 45) (S64, 45,45) 1200