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
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
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
Cellulose Nanofibrils (CNF) Enzymatic + Mechanical Functionality, Dispersion Energy cost 1. Thermal Stability 2. Functionality/dispersion 3. Chemical Recovery/Sustainability 4. Cost / Forest management
Production of Cellulose Nanocrystals (CNC) Elementary fibril Rowland and Roberts 1972. J Polym Sci Part A-1 Polym Chem 10:2447-2461. Busse-Wicher et al. (2014), The Plant J. 79:492-506
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
Effects of Acid Concentration Chen et al., Cellulose, 22:1753-1762, 2015 80 Maximal CNC yield exp (%) 60 40 20 L 21 = 228 S = 6.0 CrI = 75.5 L 21 = 174 S = 7.6 CrI = 76 L 21 = 131 S = 6.8 CrI = 75.4 0 48 52 56 60 64 68 Sulfuric acid concentration (wt%)
Dicarboxylic Acid (DCA) Hydrolysis: Esterification and Carboxylation Oxalic acid Carboxylation + H 2 O Maleic acid
Experimental
Acid C (wt%) T ( C) Typical Yield Results t (min) FCSR yield (%) CNC yield (%) Reducing sugar recovery (%) Xylose recovery (%) Glucose recovery (%) O 30 80 240 97.2±0.4 ND 1.5 50 90 180 92.7±0.5 2.3±0.0 4.8 100 30 93.2±0.1 4.5±0.1 7.2 9.62 0.65 50 100 45 91.4±0.2 8.3±0.0 7.2 60 91.5±0.4 8.1±0.1 9.2 11.6 1.2 50 100 90 88.5±0.5 11.0±0.1 10.3 11.6 2.1 240 75.1±0.1 15.8±0.2 13.9 14.7 5.0 120 45 86.7±0.3 12±0.0 8.5 60 100 45 89.1±0.3 9.0±0.2 10.3 90 87.3±0.5 11.0±0.3 12.5 120 45 76.7±0.5 11.2±0.0 13.7 70 100 45 80.8±0.7 11.4±0.2 14.9 70 100 60 73.5±0.3 24.7±0.2 16.3 120 15 73.5±0.3 12±0.0 13.4 M 50 100 45 95.9±0.3 1.1±0.0 ND 60 100 45 95.3±2.3 3.9±0.0 ND 70 100 45 83.9±0.4 12.0±0.0 ND 80 100 45 92.6±0.9 8.7±0.0 ND 120 45 85.2±0.5 10.3±0.0 ND
DCA-CNC: Morphology 13.4 Aspect Ratio: 22.8 14.6 27.3 Scale = 5 µm Scale = 500 nm
DCA - Esterification Absorption (%) 50 40 30 20 10 Transmittance 1737 2000 1900 1800 1700 1600 1500 Wavenumber (cm -1 ) 3319 2885 BEP (O70,100, 60) (M60, 100, 45) 1737 1640 1429 1317 1157 1018 896 0 4000 3500 3000 2500 2000 1500 1000 Wavenumber (cm -1 )
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) -38.0 ± 0.3 0.11 82.8 (O60, 100, 45) 1692-41.9 ± 0.7 0.15 82.4 (O70, 100, 45) 1772-43.3 ± 0.9 0.19 81.2 (O50, 100, 90) 1622-38.7 ± 0.6 0.17 81.3 (O60, 100, 90) -45.0 ± 0.3 0.39 80.0 (O70, 100, 60) 1630-42.5 ± 0.5 0.23 80.4 (M50, 100, 45) -30.1 ± 0.4 (M60, 100, 45) -31.3 ± 0.2 (M70, 100, 45) -33.3 ± 0.7 (S64, 45, 45) 1333-59.4 ± 0.8 77.9 ± 0.2 (PA, 67,45) 1960-23.0 ± 0.6 (H14, 100, 45) 1954-21.9 ± 0.7
DCA-CNC: Thermal Stability Weight (%) dw/dt (%/ o C) 100 80 60 40 20 0-4 -8-12 -16 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) 322 4.99 323 296 (M60,100, 45) 301 5.40 297 (T50, 100, 45) 299 5.20 297 (B50, 100, 45) 307 5.25 304 BEP 274 2.75 290 (P67, 100, 45) 268 3.84 277 292-20 200 220 240 260 280 300 320 340 360 380 400 420 Temperature ( o C) b (S64, 45, 45) 218 5.05 217 (H14, 100,45) 284 4.65 287 295
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
DCA Recovery: Crystallization
DCA-CNF: Morphology (O50, 100, 45) Aspect Ratio: ~120 ~ 100 93 1 µm 1 µm 1 µm A (O50, 100, 45) B (O60, 100, 45) C (O70, 100, 45)
DCA Carboxylation, Charge, DP CNC Sample CNF Charge (mv) CNF COOH (mmol/g) CNC Charge (mv) CNC COOH (mmol/g) BEP (O50, 100, 45) -28.1 ± 0.8 0.13-38.0 ± 0.3 0.11 (O60, 100, 45) -38.2 ± 0.8 0.16-41.9 ± 0.7 0.15 (O70, 100, 45) -41.6 ± 0.5 0.15-43.3 ± 0.9 0.19 (O50, 100, 90) -35.7 ± 1.8 0.18-38.7 ± 0.6 0.17 (O60, 100, 90) -39.5 ± 1.3 0.18-45.0 ± 0.3 0.39 (O70, 100, 60) -47.0 ± 0.7 0.21-42.5 ± 0.5 0.23 (S64, 45, 45) -59.4 ± 0.8 (PA, 67,45) -23.0 ± 0.6 (H14, 100, 45) -21.9 ± 0.7 (O50, 100, 45) : 287 ND (O60, 100, 45) : 265 DP of FCSR : 18 (O70, 100, 45) : 239
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, 100 60) Acetic acid: 40wt% Maleic anhydride (MAH): 20wt% 1.51 (O50, 100, 60) = Oxalic acid 50wt% at 100 o C for 60 min
Using Combined Hydrolysis Factor (CHF) Control DP and CNF Morphology (M55, 100, 60) FCSR DP = 319 1100 DP 1000 900 800 700 600 500 400 300 200 100 1E-4 0.001 0.01 0.1 1 10 100 CHF (min.mol/l) (M75, 120, 120) FCSR DP = 206 Scale Bar = 1 µm 20
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
DCA-CNC: Diameter distribution Probability density (1/nm) 0.20 0.18 0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 (O50, 100, 45) (O60, 100, 45) (O70, 100, 45) (O50, 100, 90) 0.00 0 10 20 30 40 50 Crystal height (nm)
Probability density (1/nm) 0.30 0.25 0.20 0.15 0.10 0.05 Extent of Fibrillation: Diameter Distribution Passes 1 3 5 0.00 0 5 10 15 20 Fibril height (nm)
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
2000 DCA-CNC: NMR Water Interaction 1800 1600 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