VIII
4
Rheology in Processing of Polymeric Composites ....................................................... 79
4.1
Fundamentals of Rheology ............................................................................................................... 80
4.1.1 Viscometry ............................................................................................................................................... 81
4.1.2 Viscoelasticity .......................................................................................................................................... 86
4.2
Rheology Aspects of a Polymeric Matrix ..................................................................................... 90
4.3
Rheology in Material Selection ....................................................................................................... 92
4.3.1 Rheology in Deciding Processing Conditions ............................................................................... 93
4.3.2 Rheology of Incorporation of Elastomer ........................................................................................ 94
4.3.3 Rheology in the Dispersion of Fillers ............................................................................................... 94
4.4
Flow Behaviour When Processing Composites ......................................................................... 95
4.4.1 Fibre Aspect Ratio .................................................................................................................................. 96
4.4.2 Fibre Content .......................................................................................................................................... 96
4.4.3 Dependence of Processing on Rheology ....................................................................................... 98
4.4.4 Change of Viscosity with Time and Temperature ........................................................................ 98
4.5
Rheology and Processability ............................................................................................................ 99
4.5.1 Optimization of Process Conditions ................................................................................................ 99
4.5.2 Determination of Processing Window ............................................................................................ 100
4.5.3 Fibre Dispersion and Orientation ..................................................................................................... 104
4.5.4 Troubleshooting ..................................................................................................................................... 105
4.6
Influence of Rheology on Composite Products ........................................................................ 107
4.6.1 Product Shrinkage ................................................................................................................................. 108
4.6.2 Surface Properties ................................................................................................................................. 109
4.6.3 Rheology in Structure–Property Correlation ................................................................................ 109
4.7
Rheological Measurement ................................................................................................................ 109
4.7.1 Viscoelastic Measurements................................................................................................................. 109
4.7.2 Steady Shear Rheology ........................................................................................................................ 111
4.7.3 Elastic Behaviour .................................................................................................................................... 113
References ................................................................................................................................................ 115
5
Processability of Thermosetting Composites.................................................................. 117
5.1
Interface and Interphase in Thermosetting Composites....................................................... 118
5.1.1 Glass Fibres .............................................................................................................................................. 119
5.1.2 Carbon Fibre ............................................................................................................................................ 121
5.1.3 Aramid Fibres .......................................................................................................................................... 123
5.2
Physical Forms of Reinforcements ................................................................................................. 123
5.3
Thermosetting Composites .............................................................................................................. 124
5.3.1 Curing of Thermosetting Composites ............................................................................................. 125
5.3.2 Selection Criteria for Thermosetting Matrices .............................................................................. 128
5.3.3 Processability of Commonly Used Thermosetting Matrices .................................................... 133
5.3.4 Selection Criteria for Reinforcement ............................................................................................... 137
5.4
Methods to Improve Processability in Thermosetting Composites .................................. 140
5.4.1 Adsorption and Wetting ...................................................................................................................... 140
5.4.2 Chemical Bonding ................................................................................................................................. 141
5.4.3 Mechanical Adhesion ........................................................................................................................... 141
5.4.4 Interdiffusion ........................................................................................................................................... 142
5.4.5 Electrostatic Attraction ........................................................................................................................ 142
5.5
Processability of Thermosetting ‘Green Composites’ ............................................................. 144
5.6
Processability of Smart and Intelligent Composites ............................................................... 146
5.6.1 Processability of Smart Composites ................................................................................................ 146
5.6.2 Processability of Intelligent Composites ........................................................................................ 146
References ................................................................................................................................................ 148
Contents
4
Rheology in Processing of Polymeric Composites ....................................................... 79
4.1
Fundamentals of Rheology ............................................................................................................... 80
4.1.1 Viscometry ............................................................................................................................................... 81
4.1.2 Viscoelasticity .......................................................................................................................................... 86
4.2
Rheology Aspects of a Polymeric Matrix ..................................................................................... 90
4.3
Rheology in Material Selection ....................................................................................................... 92
4.3.1 Rheology in Deciding Processing Conditions ............................................................................... 93
4.3.2 Rheology of Incorporation of Elastomer ........................................................................................ 94
4.3.3 Rheology in the Dispersion of Fillers ............................................................................................... 94
4.4
Flow Behaviour When Processing Composites ......................................................................... 95
4.4.1 Fibre Aspect Ratio .................................................................................................................................. 96
4.4.2 Fibre Content .......................................................................................................................................... 96
4.4.3 Dependence of Processing on Rheology ....................................................................................... 98
4.4.4 Change of Viscosity with Time and Temperature ........................................................................ 98
4.5
Rheology and Processability ............................................................................................................ 99
4.5.1 Optimization of Process Conditions ................................................................................................ 99
4.5.2 Determination of Processing Window ............................................................................................ 100
4.5.3 Fibre Dispersion and Orientation ..................................................................................................... 104
4.5.4 Troubleshooting ..................................................................................................................................... 105
4.6
Influence of Rheology on Composite Products ........................................................................ 107
4.6.1 Product Shrinkage ................................................................................................................................. 108
4.6.2 Surface Properties ................................................................................................................................. 109
4.6.3 Rheology in Structure–Property Correlation ................................................................................ 109
4.7
Rheological Measurement ................................................................................................................ 109
4.7.1 Viscoelastic Measurements................................................................................................................. 109
4.7.2 Steady Shear Rheology ........................................................................................................................ 111
4.7.3 Elastic Behaviour .................................................................................................................................... 113
References ................................................................................................................................................ 115
5
Processability of Thermosetting Composites.................................................................. 117
5.1
Interface and Interphase in Thermosetting Composites....................................................... 118
5.1.1 Glass Fibres .............................................................................................................................................. 119
5.1.2 Carbon Fibre ............................................................................................................................................ 121
5.1.3 Aramid Fibres .......................................................................................................................................... 123
5.2
Physical Forms of Reinforcements ................................................................................................. 123
5.3
Thermosetting Composites .............................................................................................................. 124
5.3.1 Curing of Thermosetting Composites ............................................................................................. 125
5.3.2 Selection Criteria for Thermosetting Matrices .............................................................................. 128
5.3.3 Processability of Commonly Used Thermosetting Matrices .................................................... 133
5.3.4 Selection Criteria for Reinforcement ............................................................................................... 137
5.4
Methods to Improve Processability in Thermosetting Composites .................................. 140
5.4.1 Adsorption and Wetting ...................................................................................................................... 140
5.4.2 Chemical Bonding ................................................................................................................................. 141
5.4.3 Mechanical Adhesion ........................................................................................................................... 141
5.4.4 Interdiffusion ........................................................................................................................................... 142
5.4.5 Electrostatic Attraction ........................................................................................................................ 142
5.5
Processability of Thermosetting ‘Green Composites’ ............................................................. 144
5.6
Processability of Smart and Intelligent Composites ............................................................... 146
5.6.1 Processability of Smart Composites ................................................................................................ 146
5.6.2 Processability of Intelligent Composites ........................................................................................ 146
References ................................................................................................................................................ 148
Contents