Controlling the Morphology of Polymers (eBook)

Geoffrey R Mitchell, Vice-Director, at the Center for Rapid and Sustainable Product Development of the Polytechnic Institute of Leiria.Ana Tojeira is a Research Fellow in the Centre for Rapid and Sustainable Product at the Polytechnic Institute of Leiria, which she joined in 2010. She completed her  undergraduate studies in Biomechanics in 2009 and master degree in Design and Product Development in 2012 at the same institute. She has been a member of the Associazione Italiana di Scienza e Tecnologia delle Macromolecole since 2013. Her research interests lie in the field of Biomaterials, especially applied to Tissue Engineering and Regenerative Medicine. In recent years, she has focused on the study of the morphology of biodegradable scaffolds for Bone Tissue Engineering.

Preface 8
Contents 12
Chapter 1: Scales of Structure in Polymers 14
1.1 Introduction 14
1.2 Types of Bonds 14
1.3 Types of Polymers 15
1.4 Types of Materials 17
1.4.1 Thermoplastics 18
1.4.2 Thermosets 18
1.4.3 Composites, Micro-Fillers, Nano-Fillers 19
1.5 Types of Order 20
1.5.1 Crystalline 20
1.5.2 Liquid Crystalline 20
1.5.3 Amorphous 21
1.5.4 Blends and Mixtures 21
1.6 Structuring Processes 21
1.6.1 Crystallization 21
1.6.1.1 Lamellae to Spherulites 22
1.6.1.2 Crystal Growth Rates 23
1.6.1.3 Primary and Secondary Nucleation 24
1.6.1.4 Folding Theories 25
1.6.1.5 Computer Modelling Theories 26
1.6.1.6 The Bell Curve 26
1.6.1.7 Nucleation 27
1.6.1.8 Crystallization in Practice 27
1.6.1.9 Crystallization and Orientation 28
1.6.2 Microphase Separation and Block Copolymers (BCP) 28
1.6.2.1 Photonic Crystals 32
1.6.2.2 Micelles 32
1.6.3 Phase Separation Mixtures 33
1.6.4 Phase Separation on Reaction 35
1.7 Large-Scale Processes 36
1.8 Summary 37
References 37
Chapter 2: Evaluating Scales of Structures 42
2.1 Introduction 42
2.2 Indirect Methods 43
2.2.1 Differential Scanning Calorimetry 43
2.2.1.1 Reorganization and `Morphological Melting´ 46
2.2.1.2 Thermal Fractionation 47
2.2.2 Dynamics 49
2.2.3 Spectroscopy 49
2.3 Imaging Methods 50
2.3.1 Light Microscopy 50
2.3.1.1 Polarized Optical Microscopy (POM) 52
2.3.1.2 Use of Tint Plates 53
2.3.1.3 Circularly Polarized Light 54
2.3.1.4 Phase Contrast Microscopy 55
2.3.1.5 Interference Microscopy (Nomarski) 56
2.3.1.6 Ancillary Techniques 58
2.3.2 Scanning Electron Microscopy 58
2.3.2.1 Contrast 59
2.3.2.2 Sandwiching and Embedding Techniques 60
2.3.3 Etching 61
2.3.4 Transmission Electron Microscopy 63
2.3.4.1 Inducing Contrast 63
2.3.5 Atomic Force Microscopy 66
2.4 Scattering Methods 66
2.4.1 X-Ray Scattering 67
2.4.1.1 Small Angle X-Ray Scattering 67
2.4.1.2 Wide Angle X-Ray Scattering 68
2.4.1.3 SAXS/WAXS Instruments 70
2.4.2 Neutron Scattering 71
2.4.2.1 Small Angle Neutron Scattering 72
2.4.2.2 Broad Q Neutron Diffraction 72
2.4.2.3 Neutron Scattering Instruments 74
2.5 Summary 76
References 76
Chapter 3: Crystallization in Nanocomposites 81
3.1 Introduction 81
3.2 Templating 82
3.2.1 Linear Nucleation 82
3.3 Crystallization and Flow 84
3.4 Nanoparticles 87
3.4.1 Introduction 87
3.4.2 Carbon Nanotubes 88
3.4.3 Nanoclay 93
3.5 Nanocomposites with Carbon Nanotubes 98
3.5.1 Nanocomposites with Halloysites 100
3.5.2 Nanocomposites with Clay Platelets 101
3.5.3 Nanocomposites with Graphene 104
3.5.4 Summary 106
References 107
Chapter 4: Theoretical Aspects of Polymer Crystallization 113
4.1 Introduction 113
4.2 Thermodynamics of Polymer Crystallization 114
4.2.1 Basic Concepts 114
4.2.2 Statistical Thermodynamics of Polymer Crystallization 120
4.2.3 Properties of Equilibrium Melting Points 122
4.2.3.1 Interaction Parameters 122
4.2.3.2 Molecular Weights 123
4.2.3.3 Comonomer Contents in Random Copolymers 125
4.2.4 Phase Diagrams of Polymer Solutions 126
4.3 Kinetics of Polymer Crystallization 129
4.3.1 Crystal Nucleation 129
4.3.2 Crystal Growth 137
4.3.2.1 Secondary Nucleation Models 137
4.3.2.2 Other Non-nucleation Models 144
4.3.3 Crystal Annealing 147
4.4 Summary 149
References 150
Chapter 5: Controlling Morphology Using Low Molar Mass Nucleators 156
5.1 Introduction 156
5.2 Organic Gelators 158
5.3 Synthesis of Sorbitol Derivatives 159
5.4 DBS in Polymers 160
5.5 DBS Directing Crystallisation 166
5.6 Model of Directed Crystallisation 169
5.7 Summary 170
References 171
Chapter 6: Crystallization in Nanoparticles 173
6.1 Introduction 173
6.2 Generation of Polymer Nanoparticles 175
6.3 Modification of the Crystalline Morphology by Confinement into Nanoparticles 177
6.3.1 Crystallization in Nanoparticles 180
6.3.2 From Polymer Nanoparticles to Polymer Nanocrystals 183
6.4 Summary 185
6.5 Methods 186
Bibliography 186
Chapter 7: Controlling Morphology in 3D Printing 191
7.1 Introduction 191
7.1.1 Light-Based Technologies 193
7.1.2 Print-Based Technologies 194
7.1.3 Extrusion-Based Technologies: Melt or Solution 194
7.1.3.1 Fused Deposition Modelling/Fused Filament Fabrication 194
7.2 FDM/FFF Feedstock Materials 195
7.3 Parameters in FDM/FFF 3D Printers 197
7.3.1 Surface 198
7.3.1.1 Layer Thickness 198
7.3.1.2 Part Orientation 198
7.3.2 Layer and Cross-Section 199
7.3.2.1 Gap Between Filaments 199
7.3.2.2 Layer Patterning 201
7.3.2.3 Materials Properties 201
7.3.3 Filaments 203
7.4 Case Study 1: Feedstock Material 204
7.5 Case Study 2: Deposition Speed 206
7.6 Case Study 3: Feed Roller Velocity/Screw Rotation Velocity 208
7.7 Case Study 4: Extrusion Temperature 211
7.8 Summary 214
References 214
Chapter 8: Electrically Conductive Polymer Nanocomposites 218
8.1 Introduction 218
8.2 Percolation Theory 219
8.2.1 Electrical Conductivity Mechanisms 223
8.3 Filler Effects on Polymer Nanocomposites 229
8.3.1 Aspect Ratio 229
8.3.2 Polydispersity 230
8.3.3 Orientation 232
8.3.4 Dispersion and Filler Localisation 233
8.3.5 Rheology and Mechanical Properties 236
8.3.6 Crystallisation and Morphology 239
8.4 Summary 241
References 242
Chapter 9: Nanodielectrics: The Role of Structure in Determining Electrical Properties 246
9.1 Introduction 246
9.1.1 Nanotechnology 247
9.1.2 Nanocomposites: Scales of Structure 248
9.2 Nanodielectric Properties 249
9.2.1 Surface Electrical Properties of Nanodielectrics 249
9.2.1.1 Resistance to Corona and Surface Discharges 249
9.2.1.2 Degradation of Nanocomposites: Mechanisms 250
9.2.2 Bulk Electrical Properties of Nanodielectrics 252
9.2.2.1 Breakdown Strength 252
9.2.2.2 Permittivity 254
9.2.3 Nanoparticles as Structural Modifiers 258
9.3 Theories and Models 260
9.3.1 Miscibility and Dispersion 260
9.3.2 Interfaces and Interphases 262
9.3.3 From Composition to Properties 263
9.4 Advanced Dielectrics Through Morphological Design 264
9.4.1 Polyethylene Blends 265
9.4.2 Polypropylene Blends 267
9.5 Summary 269
References 269
Chapter 10: Block Copolymers and Photonic Band Gap Materials 272
10.1 Introduction 272
10.1.1 Phase Behaviour of Block Copolymers 273
10.2 Photonic Band Gap Materials 276
10.3 Synthesis of Block Copolymers 280
10.3.1 Characterisation of Photonic Band Gap Materials 287
10.3.2 Extending to Longer Wavelengths 288
10.4 Conclusion 291
References 291
Chapter 11: Relationship Between Molecular Configuration and Stress-Induced Phase Transitions 295
11.1 Introduction 295
11.2 Isotactic Polypropylene Samples 298
11.3 Structural Analysis and Mechanical Properties 299
11.4 Optical and Atomic Force Microscopy 304
11.5 Stress-Induced Phase Transitions in Unoriented Films 307
11.6 Structural Analysis at Microscopic Length Scale 312
11.7 Structural Analysis at Lamellar Length Scale 318
11.8 Determination of Damage Effect 324
11.9 Concluding Remarks 328
References 331
Chapter 12: Summary 336
References 337
Index 338