Contents
Preface xiii
1 Introduction 1
1.1 Introduction 1
1.2 Classification of textile fibres based on sources 1
1.2.1 Vegetable sources 1
1.2.2 Animal sources 2
1.2.3 Ground and petrochemical sources 3
1.3 Classification of textile fibres based on polymer 3
1.4 Concept of fibre science 5
1.5 Concept of fibre science 6
2 Chemical structure 11
2.1 Introduction 11
2.2 Raw materials 11
2.3 Polymer molecule 12
2.4 Chemical bonding in polymers 15
2.5 Chemical structure 16
2.6 Classification of polymers 17
2.7 Polymer structure phases 21
2.8 Configuration 22
2.9 Isomerism 22
2.10 Tacticity 25
2.11 Rotational isomerism or conformations 27
2.12 Model of a molecular chain 28
2.13 Mathematical derivation of end-to-end distance 31
2.14 Radius of gyration 35
2.15 Excluded volume effect 36
2.16 Role of solvent on conformation 36
2.17 Conformation and chain flexibility 37
2.18 Chain structure in selected fibres/polymers 37
2.18.1 Polyethylene 37
2.18.2 Proteins 38
3. Crystalline structure 41
3.1 Introduction 41
3.2 Intermolecular forces 41
3.3 Crystal structure 43
3.3.1 Crystal structure of cellulose 45
3.3.2 Crystal structure of silk 47
3.3.3 Crystal structure of wool 49
3.3.4 Crystal structure of polyethylene and polypropylene 51
3.3.5 Crystal structure of Polyamide 6 52
3.3.6 Crystal structure of Polyamide n 54
3.3.7 Crystal structure of Polyamide 6,6 55
3.3.8 Crystal Structure of Polyamide m, n 56
3.3.9 Crystal structure of poly (ethylene terephthalate) 57
3.3.10 Crystal structure of polyacrylonitrile 58
4 Amorphous structure 61
4.1 Introduction 61
4.2 Amorphous solids 63
4.3 Glass transition temperature 64
4.4 Theories of glass transition 67
4.4.1 Free volume theory 67
4.4.2 Barrier theory 69
4.4.3 Statistical theory 71
4.5 Chemical structure and Tg 72
4.6 Structural factors and Tg 73
4.7 Measurement of Tg 75
4.7.1 Specifi c volume method 75
4.7.2 DSC or DTA 76
4.7.3 Relaxation method 76
4.7.4 Chemical method 76
4.8 Molecular relaxation 76
4.9 Properties dependent on amorphous region 79
5 Morphology 83
5.1 Molecular architecture 83
5.2 Two phase structure 84
5.3 Models of fibre structure 85
5.3.1 The fringed-micelle model 85
5.3.2 The fringe-fibril model 87
5.4 Three phase structure 88
5.5 Crystalline relaxations 89
5.6 Crystallinity 90
5.6.1 X-ray diffraction 91
5.6.2 Density measurements 91
5.6.3 Calorimetry 91
5.6.4 Infrared spectroscopy 91
5.7 Fibre structure and properties 92
5.8 Liquid crystal polymer (LCP) 93
6 Crystallization 97
6.1 Introduction 97
6.2 Crystallization process 97
6.2.1 Nucleation 98
6.2.2 Growth 99
6.3 Polymer crystallization 100
6.4 Theory of crystallization kinetics 100
6.4.1 Primary crystallization 100
6.4.2 Secondary crystallization 101
6.5 Crystallization rate 102
6.6 Types of crystallization 105
6.6.1 Melt crystallization 105
6.6.2 Solvent-induced crystallization 106
6.6.3 Strain-induced crystallization 109
6.6.4 Crystallization concurrent with chain growth 112
6.7 Crystallization of polyamide 6 112
6.8 Crystallization of poly (ethylene terephthalate) 114
6.9 Melting 114
6.10 Thermal methods of analysis 118
7 Orientation 121
7.1 Introduction 121
7.2 Orientation factor 122
7.3 Crystallite orientation 125
7.4 Limiting cases of orientation 126
7.5 Measurement of orientation 127
7.5.1 Birefringence 127
7.5.2 X-ray diffraction 130
7.5.3 Small angle x-ray scattering 131
7.5. 4 Infrared spectroscopy 131
7.5.5 Raman spectroscopy 132
7.5.6 uclear magnetic resonance (NMR) spectroscopy 132
7.5.7 Sonic velocity 132
7.6 Orientation process 133
7.7 Importance of orientation 134
7.8 Deformation behaviour of fibres 135
7.9 Orientation and anisotropic properties 136
8 Measurement of structures 139
8.1 Introduction 139
8.2 Methods for investigation of configuration and conformation 140
8.3 Methods for investigation of crystallites and crystallinity 142
8.4 Methods for investigation of amorphous state 144
8.5 Methods for investigation of orientation state 144
8.6 Overall observations 145
9 Microscopy methods 147
9.1 Introduction 147
9.1.1 Applications 148
9.2 Light microscopy 149
9.2.1 Parameters of light microscope 149
9.2.2 Types of microscopes 150
9.3 Transmission light microscopy 150
9.4 Reflected light microscopy 152
9.5 Dark field microscopy 152
9.6 Fluorescence microscopy 153
9.7 Confocal microscopy 154
9.8 Polarized microscopy 154
9.9 Phase contrast microscopy 155
9.10 Interference microscopy 157
9.11 Advantages and disadvantages of light microscopy 158
9.12 Electron microscopy 158
9.12.1 Advantages of electron microscopes 159
9.12.2 Disadvantages of electron microscopes 159
9.13 Transmission electron microscopy (TEM) 163
9.13.1 Limitations 164
9.13.2 Microscopy sample preparation: microtomes and ultramicrotomes 165
9.14 Scanning electron microscopy (SEM) 165
9.15 Scanned probe microscopy (SPM) 166
10. Diffraction methods 169
10.1 Introduction 169
10.2 X-ray diffraction 170
10.3 Information from XRD 171
10.4 Degree of crystallinity 172
10.4.1 Crystallinity percentage 173
10.4.2 Crystallinity index 175
10.5 Microstructure 177
10.6 Indexing of crystal structures 178
10.7 Electron diffraction (ED) 179
10.8 Electron interaction with matter 179
10.9 Techniques of electron diffraction 180
10.9.1 Low-energy electron diffraction 180
10.9.2 High-energy electron diffraction 181
10.10 Transmission electron microscope 181
10.11 Scanning electron microscope 182
10.12 Scanning and transmission electron microscope 182
11 Scattering techniques 185
11.1 Introduction 185
11.2 Small-angle x-ray scattering (SAXS) 185
11.2.1 Instrumentation 187
11.2.2 Utilization 187
11.2.3 Structural information from SAXS 189
11.3 Small-angle light scattering (SALS) 189
11.3.1 Theory of small angle light scattering 190
11.3.2 Instrumentation 191
11.4 Small-angle neutron scattering 192
12 Spectroscopic methods 195
12.1 Introduction 195
12.2 Electronic spectroscopy 196
12.3 Vibrational spectroscopy 197
12.4 Infrared spectroscopy 197
12.4.1 Fundamental vibrations 199
12.4.2 Analysis of infrared spectrum 201
12.4.3 Measurement of crystallinity by IR spectroscopy 202
12.4.4 Tacticity and conformation 204
12.4.5 Chain folding 204
12.4.6 Measurement techniques in IR spectroscopy 204
12.5 Raman spectroscopy 206
12.5.1 Advantages of Raman spectroscopy 207
12.5.2 Measurement of crystallinity by Raman spectroscopy 207
12.6 Fourier transform infrared spectroscopy 208
12.7 Resonance spectroscopic methods 209
12.7.1 Spin resonance 209
12.7.2 Nuclear resonance 210
12.7.3 Nuclear magnetic moments 210
12.8 Nuclear magnetic resonance spectroscopy (NMR) 211
12.8.1 Nuclear magnetic resonance of polymers 213
12.9 Electron spin-resonance spectroscopy (ESR) 214
Index 217