Polypropylene Nanofibers (eBook)

Acknowledgements 6
Contents 7
Abbreviations 11
Symbols 12
Abstract 13
1 Introduction 15
1.1 Scope 15
1.2 Research Concepts and Hypotheses 17
1.3 Aims and Objectives 18
1.4 Contribution of the Research 19
1.5 Conclusion 19
References 20
2 Review of Literature: Melt Electrospinning 22
2.1 Introduction 22
2.2 Electrospinning 22
2.2.1 Types of Electrospinning 23
2.2.1.1 Solution Electrospinning 23
2.2.1.2 Melt Electrospinning 24
2.2.2 Jet Trajectory 25
2.3 Research on Melt Electrospinning 39
2.3.1 Equipment Used 39
2.3.2 Polymers Used 40
2.4 Fibre Diameter and Influencing Factors 41
2.4.1 Effects of Molecular Weight/MFI 42
2.4.2 Effect of Viscosity 42
2.4.3 Effect of Applied Voltage 42
2.4.4 Effect of Collector Distance and Type 43
2.4.5 Effect of Flow Rate 43
2.4.6 Effect of Spinneret Size 44
2.4.7 Effect of Temperature 44
2.4.8 Effect of Ambient Parameters 44
2.4.9 Effect of Electrical Conductivity 45
2.4.10 Other Parameters 45
2.5 Surface Morphology 45
2.6 Properties of Melt Electrospun Fibres 46
2.6.1 Mechanical Properties 46
2.6.2 Thermal Properties 47
2.6.3 Crystalline Properties 47
2.6.4 Other Properties 48
2.7 Conclusion 49
References 49
3 Experimental: Melt Electrospinning 53
3.1 Introduction 53
3.2 Materials 53
3.2.1 Material Synthesis 54
3.2.2 Material Preparation 55
3.3 Melt Electrospinning Apparatus 56
3.4 Additives 59
3.5 Annealing 59
3.6 Characterisation 60
3.6.1 SEM 60
3.6.2 Optical Microscopy 60
3.6.3 EDX 60
3.6.4 NMR 61
3.6.5 FTIR 61
3.6.6 DSC 61
3.6.7 TGA 62
3.6.8 Molecular Weight or Intrinsic Viscosity 62
3.6.9 XRD 62
3.6.10 Shear Viscosity 63
3.6.11 Electrical Conductivity 64
3.6.12 Mechanical Characterisation 64
3.6.13 Surface Wettability 65
3.7 Conclusion 65
References 65
4 Results and Discussion: Melt Electrospinning 67
4.1 Initial Experiments with Pure Polymers 67
4.1.1 Establishing the Processing Parameters 67
4.1.1.1 Temperature 68
4.1.1.2 Applied Voltage 69
4.1.1.3 Collector Distance 69
4.1.1.4 Melt Flow Rate 70
4.1.1.5 Spinneret Size 70
4.1.2 Initial Results: Effect of Polymer MFI 71
4.1.3 Effect of Viscosity 73
4.1.4 Effect of Melt Flow Rate 75
4.1.5 Other Observations 76
4.1.6 Effect of Die Size and Shape 77
4.1.6.1 Effect of Die Size 79
4.1.6.2 Effect of Die Shape 81
4.2 Experiments with Additives 82
4.2.1 Effect of Additives on Fibre Diameter 83
4.2.1.1 Fibre Diameter from 100 and 300 MFI 83
4.2.1.2 Fibre Diameter from 1000 and 2000 MFI 83
4.2.1.3 Effect of Viscosity 91
4.2.1.4 Effect of Electrical Conductivity 92
4.2.1.5 Optimum Concentration of SO and NaCl 94
4.3 Characterisation 96
4.3.1 Elemental Composition Analysis by Energy Dispersive X-ray (EDX) 96
4.3.2 Nuclear Magnetic Resonance (NMR) Results 99
4.3.3 Fourier Transform Infrared (FTIR) Results 100
4.3.4 Differential Scanning Calorimetry (DSC) Results 101
4.3.5 Thermo Gravimetric Analysis (TGA) Results 108
4.3.6 Molecular Weight or Intrinsic Viscosity 108
4.3.7 X-ray Diffraction (XRD) Results 109
4.3.8 Mechanical Property 111
4.3.9 Hydrophobic Properties 112
4.4 Washing of the Additives 113
4.5 Conclu?sion 115
References 115
5 Conclusions: Melt Electrospinning 118
5.1 Conclusions 118
References 120
6 Review of Literature: Meltblowing 121
6.1 Meltblowing 121
6.1.1 Equipment 121
6.1.2 Fibre Diameter and Influencing Factors 122
6.1.2.1 Effects of Material Properties 124
6.1.2.2 Effects of Process Parameters 125
6.1.3 Properties of Meltblown Fibres 125
6.2 Conclusio?n 126
References 126
7 Experimental: Meltblowing 129
7.1 Introduction 129
7.2 Materials 129
7.3 Meltblowing Apparatus 130
7.4 Annealing 133
7.5 Characterisation 133
7.5.1 Optical Microscopy 133
7.5.2 SEM 133
7.5.3 NMR 134
7.5.4 FTIR 134
7.5.5 DSC 134
7.5.6 TGA 135
7.5.7 Molecular Weight or Intrinsic Viscosity 135
7.5.8 XRD 135
7.5.9 Shear Viscosity 136
7.5.10 Mechanical Characterisation 137
7.5.11 Surface Wettability 138
7.6 Conc?lusion 139
References 139
8 Results and Discussion: Meltblowing 140
8.1 Initial Experiments with Pure Polymers 140
8.1.1 Initial Results 140
8.2 Effect of Fluids 141
8.2.1 Process of Fibre Formation with Fluid Injection 142
8.2.2 Collection Pattern of Fibres 143
8.2.3 Mechanism of Fibre Formation 145
8.2.4 Morphology and Diameter of Fibres 148
8.2.4.1 Fibre Morphology 148
8.2.4.2 Average Fibre Diameter 150
8.2.4.3 Results for 2000 MFI PP 152
8.3 Characterisation 153
8.3.1 NMR Results 154
8.3.2 FTIR Results 155
8.3.3 DSC Results 156
8.3.4 TGA 158
8.3.5 Molecular Weight or Intrinsic Viscosity 158
8.3.6 XRD Results 159
8.3.7 Mechanical Properties 161
8.3.7.1 Effect of MFI 161
8.3.7.2 Effect of Fluid Type 163
8.3.7.3 Effect of Annealing 163
8.3.7.4 Effect of Rotating Drum on the Mechanical Property 164
8.3.8 Hydrophobic Properties 165
8.4 Processing Difficulties with 2000 MFI PP 167
8.5 Conclusion 167
References 168
9 Conclusions: Meltblowing 170
9.1 Conclusions 170
References 172
10 Comparison of Results and Future Suggestions 173
10.1 Results of the Study 173
10.2 Comparison of Results for the Fabrication of Nanofibres 174
10.2.1 Differences in the Process of Fibre Formation 174
10.2.2 Differences in the Material Performance 174
10.2.3 Differences in the Fibre Properties 175
10.3 Future Suggestions 176
10.4 Publications 177
10.4.1 Journal Publications 177
10.4.2 Conference Publications 177
10.4.3 Book Chapter 178
References 178
Appendix A: Melt Electrospinning 179
Appendix B: Meltblowing 186
Index 193