Nanocellulose (eBook)

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Alain Dufresne, Grenoble Institute of Technology, Saint Martin d'Hères, France.

Preface 7
1 Cellulose and potential reinforcement 17
1.1 Polysaccharides 17
1.2 Chemical structure of the cellulose macromolecul 19
1.3 Biosynthesis of cellulose 21
1.4 Polymorphism of cellulose 24
1.4.1 Cellulose I 24
1.4.2 Cellulose II 26
1.4.3 Cellulose III 26
1.4.4 Cellulose IV 27
1.5 Cellulose microfibrils 27
1.6 Hierarchical structure of plants and natural fibers 31
1.7 Potential reinforcement of cellulose 35
1.7.1 Mechanical properties of natural fibers 36
1.7.2 Mechanical properties of cellulose microfibrils 39
1.7.3 Mechanical properties of cellulose crystal 41
1.8 Cellulose-based materials 47
1.8.1 Thermoplastically processable cellulose derivatives 48
1.8.2 Cellulose fiber reinforced composites 49
1.9 Conclusions 50
1.10 References 51
2 Preparation of microfibrillated cellulose 59
2.1 Fiber fibrillation process 59
2.1.1 Purification of cellulose 60
2.1.2 High-pressure homogenization 61
2.1.3 Grinding 63
2.1.4 Cryocrushing 65
2.1.5 High-intensity ultrasonication 66
2.1.6 Electrospinning 67
2.2 Pretreatments 69
2.2.1 Enzymatic pretreatment 70
2.2.2 Carboxymethylation 72
2.2.3 TEMPO-mediated oxidation pretreatment 73
2.3 Morphology 74
2.4 Degree of fibrillation 78
2.4.1 Turbidity of the suspension 78
2.4.2 Viscosity of the suspension 78
2.4.3 Porosity and density 78
2.4.4 Mechanical properties 81
2.4.5 Water retention 81
2.4.6 Degree of polymerization 81
2.4.7 Specific surface area 82
2.4.8 Crystallinity 84
2.5 Mechanical properties of MFC films 85
2.6 Optical properties of MFC films 88
2.7 Functionalization of MFC films 90
2.8 Conclusions 90
2.9 References 91
3 Preparation of cellulose nanocrystals 99
3.1 Pioneering works on the acid hydrolysis of cellulose 99
3.2 Pretreatment of natural fibers 101
3.3 Acid hydrolysis treatment 102
3.3.1 Sources of cellulose 103
3.3.2 Nature of the acid 106
3.3.3 Effect and optimization of extraction conditions 108
3.4 Other processes 112
3.4.1 Enzymatic hydrolysis treatment 112
3.4.2 TEMPO oxidation 113
3.4.3 Hydrolysis with gaseous acid 114
3.4.4 Ionic liquid 115
3.5 Post-treatment of hydrolyzed cellulose 115
3.5.1 Purification of the suspension 115
3.5.2 Fractionation 115
3.5.3 Yield 117
3.6 Morphology 118
3.7 Degree of hydrolysis 124
3.7.1 Birefringence of the suspension 124
3.7.2 Viscosity of the suspension 126
3.7.3 Porosity and density 126
3.7.4 Mechanical properties 126
3.7.5 Degree of polymerization 127
3.7.6 Specific surface area 128
3.7.7 Level of sulfation 129
3.7.8 Crystallinity 130
3.8 Mechanical properties of nanocrystal films 132
3.9 Conclusions 134
3.10 References 134
4 Bacterial cellulose 141
4.1 Production of cellulose by bacteria 141
4.2 Influence of carbon source 145
4.3 Culture conditions 146
4.4 In situ modification of bacterial cellulose 149
4.5 Bacterial cellulose hydrogels 150
4.6 Bacterial cellulose films 152
4.7 Applications of bacterial cellulose 156
4.8 Conclusions 157
4.9 References 158
5 Chemical modification of nanocellulose 163
5.1 Reactivity of cellulose 163
5.2 Surface chemistry of cellulose nanoparticles 166
5.3 Non-covalent surface chemical modification of cellulose nanoparticles 168
5.3.1 Adsorption of surfactant 168
5.3.2 Adsorption of macromolecules 169
5.4 Esterification, acetylation and acylation 170
5.5 Cationization 174
5.6 Silylation 175
5.7 Carbamination 177
5.8 TEMPO-mediated oxidation 178
5.9 Polymer grafting 180
5.9.1 Polymer grafting using the “grafting onto” approach 183
5.9.2 Polymer grafting using the “grafting from” approach 185
5.10 Click chemistry 190
5.11 Fluorescently labeled nanocellulose 190
5.12 Evidence of surface chemical modification 193
5.12.1 X-ray diffraction analysis 193
5.12.2 Dispersion in organic solvent 193
5.12.3 Contact angle measurements 194
5.12.4 Gravimetry 196
5.12.5 Fourier transform infrared (FTIR) spectroscopy 196
5.12.6 Elemental analysis 197
5.12.7 X-ray photoelectron spectroscopy (XPS) 197
5.12.8 Time of flight mass spectrometry (TOF-MS) 199
5.12.9 Solid-state NMR spectroscopy 199
5.12.10 Thermogravimetric analysis (TGA) 200
5.12.11 Differential scanning calorimetry (DSC) 200
5.13 Conclusions 200
5.14 References 202
6 Rheological behavior of nanocellulose suspensions and self-assembly 209
6.1 Rheological behavior of microfibrillated cellulose suspensions 209
6.2 Stability of colloidal cellulose nanocrystal suspensions 212
6.3 Birefringence properties of cellulose nanocrystal suspensions 215
6.4 Liquid crystalline behavior 216
6.4.1 Liquid crystalline state 216
6.4.2 Liquid crystalline behavior of cellulose derivatives 219
6.4.3 Liquid crystalline behavior of cellulose nanocrystal suspensions 221
6.5 Onsager theory for neutral rod-like particles 223
6.6 Theoretical treatment for charged rod-like particles 227
6.7 Chiral nematic behavior of cellulose nanocrystal suspensions 228
6.7.1 Isotropic-chiral nematic phase separation of cellulose nanocrystal suspensions 228
6.7.2 Effect of the polyelectrolyte nature 230
6.7.3 Effect of the presence of macromolecules 234
6.8 Liquid crystalline phases of spherical cellulose nanocrystal suspensions 236
6.9 Rheological behavior of cellulose nanocrystal suspensions 237
6.10 Light scattering studies 240
6.11 Preserving the chiral nematic order in solid films 242
6.12 Conclusions 245
6.13 References 245
7 Processing of nanocellulose-based materials 251
7.1 Polymer latexes 251
7.2 Hydrosoluble or hydrodispersible polymers 254
7.3 Non-aqueous systems 258
7.3.1 Non-aqueous polar medium 259
7.3.2 Solvent mixture and solvent exchange 260
7.3.3 In situ polymerization 262
7.3.4 Surfactant 263
7.3.5 Surface chemical modification 264
7.4 Foams and aerogels 264
7.5 Melt compounding 268
7.5.1 Drying of the nanoparticles 268
7.5.2 Melt compounding with a polar matrix 270
7.5.3 Melt compounding using solvent exchange 272
7.5.4 Melt compounding with processing aids 272
7.5.5 Melt compounding with chemically grafted nanoparticles 274
7.5.6 Melt compounding using physical process 276
7.6 Filtration and impregnation 276
7.7 Spinning and electrospinning 277
7.8 Multilayer films 278
7.9 Conclusions 281
7.10 References 281
8 Thermal properties 293
8.1 Thermal expansion of cellulose 293
8.1.1 Thermal expansion coefficient of cellulose crystal 293
8.1.2 Thermal expansion coefficient of nanocellulose films 295
8.1.3 Thermal expansion coefficient of nanocellulose-based composites 295
8.2 Thermal conductivity of nanocellulose-based nanocomposites 297
8.3 Thermal transitions of cellulose nanoparticles 297
8.4 Thermal stability of cellulose nanoparticles 299
8.4.1 Thermal degradation of cellulose 299
8.4.2 Thermal stability of microfibrillated cellulose 300
8.4.3 Thermal stability of cellulose nanocrystals 302
8.4.4 Thermal stability of bacterial cellulose and electrospun fibers 308
8.5 Glass transition of nanocellulose-based nanocomposites 308
8.6 Melting/crystallization of nanocellulose-based nanocomposites 314
8.6.1 Melting temperature 314
8.6.2 Crystallization temperature 316
8.6.3 Degree of crystallinity 318
8.6.4 Rate of crystallization 323
8.7 Thermal stability of nanocellulose-based nanocomposites 326
8.8 Conclusions 329
8.9 References 329
9 Mechanical properties of nanocellulose-based nanocomposites 337
9.1 Pioneering works 337
9.2 Modeling of the mechanical behavior 339
9.2.1 Mean field approach 339
9.2.2 Percolation approach 343
9.3 Influence of the morphology of the nanoparticles 349
9.4 Influence of the processing method 351
9.5 Filler/matrix interfacial interactions 355
9.5.1 Polarity of the matrix 361
9.5.2 Chemical modification of the nanoparticles 366
9.5.3 Local alteration of the matrix in the presence of the nanoparticles 369
9.6 Synergistic reinforcement 372
9.7 Specific mechanical characterization 373
9.7.1 Compression test 373
9.7.2 Successive tensile test 374
9.7.3 Bulge test 359 16
9.7.4 Raman spectroscopy 376
9.7.5 Atomic force microscopy 377
9.8 Conclusions 378
9.9 References 378
10 Swelling and barrier properties 389
10.1 Swelling and sorption properties 389
10.2 Barrier properties 393
10.2.1 Water vapor transfer rate and water vapor permeability 393
10.2.2 Gas permeability 394
10.3 Water sorption and swelling properties of microfibrillated cellulose films 396
10.3.1 Influence of pretreatment 398
10.3.2 Influence of post-treatment 398
10.4 Water vapor transfer rate and water vapor permeability of microfibrillated cellulose films 399
10.4.1 Influence of pretreatment 399
10.4.2 Influence of post-treatment 400
10.5 Gas permeability of microfibrillated cellulose films 401
10.5.1 Effect of relative humidity 401
10.5.2 Improvement of gas barrier properties 403
10.5.3 Polymer coating 404
10.5.4 Paper coating 405
10.6 Cellulose nanocrystal films 407
10.7 Microfibrillated cellulose-based films 408
10.7.1 Swelling and sorption properties 408
10.7.2 Water vapor transfer rate and water vapor permeability 411
10.7.3 Oxygen permeability 411
10.8 Cellulose nanocrystal-based films 412
10.8.1 Swelling and sorption properties 412
10.8.2 Water vapor transfer rate and water vapor permeability 417
10.8.3 Gas permeability 418
10.8.4 Other substances permeability 420
10.9 Conclusions 420
10.10 References 421
11 Other polysaccharide nanocrystals 427
11.1 Starch 427
11.1.1 Composition 427
11.1.2 Multi-scale structure of the granule 430
11.1.3 Polymorphism 432
11.2 Acid hydrolysis of starch 433
11.3 Starch nanocrystals 435
11.3.1 Aqueous suspensions 437
11.3.2 Morphology 438
11.3.3 Thermal properties 440
11.3.4 Surface chemical modification 440
11.4 Starch nanocrystal reinforced polymer nanocomposites 442
11.4.1 Mechanical properties 442
11.4.2 Swelling properties 445
11.4.3 Barrier properties 446
11.5 Chitin 446
11.5.1 Chemical structure 447
11.5.2 Polymorphism and structure 447
11.6 Chitin nanocrystals 448
11.6.1 Acid hydrolysis 448
11.6.2 Other treatments 448
11.6.3 Morphology 450
11.6.4 Surface chemical modification 451
11.7 Chitin nanocrystal reinforced polymer nanocomposites 453
11.7.1 Mechanical properties 453
11.7.2 Swelling resistance 456
11.8 Conclusions 457
11.9 References 457
12 Conclusions, applications and likely future trends 465
12.1 References 468
13 Index 471

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"All in all, the book provides an indispensable resource for the growing number of scientists and engineers interested in the preparation and applications of nanocellulose."
Derek Gray, McGill University