Castable polyurethane elastomers

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Title:

Personal Author:

Clemitson, I. R.

Publication Information:

Boca Raton, FL : CRC, 2008

Physical Description:

250 p. : ill. ; 24 cm.

ISBN:

9781420065763

Subject Term:

Polyurethane elastomers

Polyurethanes -- Industrial applications

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Library	Item Barcode	Call Number	Material Type	Item Category 1	Status
Searching... PSZ JB	30000010201659	TP1180.P8 C53 2008	Open Access Book	Book	Searching... Unknown

Currently, raw material suppliers are the sole providers of polyurethane processing information. In most cases, they give instruction only on how to mix products and do not always include an explanation of the accompanying logic as to why these recommendations are being made.

Castable Polyurethane Elastomers explains the production process of polyurethane components from both the theoretical and practical point of view. It describes the underlying concepts for the raw material supplier recommendations and explains how to achieve application-specific properties in polyurethane . The book explains the production of prepolymers with special focus on health and safety issues. It presents the different types of methods available on both the micro and macro levels and explains the rationale behind choosing the system needed to create a cost-effective, application-specific product.

Offering an inside look at the logic behind the formation of polyurethane components, Castable Polyurethane Elastomers enables materials scientists, engineers, and chemists to understand the total production process and reproduce the procedures to achieve desired results.

1 Introduction	p. 1
1.1 What Are Polyurethanes?	p. 1
1.1.1 Discovery of Polyurethanes	p. 2
1.2 Polyurethane Family	p. 3
1.2.1 Fibers	p. 3
1.2.2 Films	p. 3
1.2.3 Castables Background	p. 3
1.2.4 Thermoplastics	p. 4
1.2.5 Foams	p. 4
1.2.6 Millable	p. 4
1.3 Castable Polyurethanes	p. 5
1.3.1 Advantages of Polyurethanes	p. 5
1.3.2 Applications	p. 5
2 Chemistry	p. 7
2.1 Introduction	p. 7
2.1.1 Background	p. 7
2.1.2 Basic Reactions of Urethanes	p. 9
2.2 Raw Materials	p. 13
2.2.1 Polyols	p. 13
2.2.2 Diisocyanates	p. 16
2.2.3 Chain Extenders	p. 19
2.2.4 Other Chemicals	p. 23
2.3 Prepolymers	p. 24
2.3.1 Commercial Preparation of Prepolymers	p. 24
2.3.2 One-Shot System	p. 27
2.4 Urea and Urethane Reactions	p. 28
2.4.1 Introduction	p. 28
2.4.2 Speed	p. 28
2.5 Chain Extension	p. 29
2.5.1 Urea	p. 29
2.5.2 Urethane	p. 31
2.5.3 Hydrogen Bonding	p. 31
2.5.4 Three-Dimensional Cross-Linking	p. 34
2.5.5 Catalysts	p. 35
2.6 Degradation	p. 37
2.6.1 Prepolymers	p. 37
2.6.2 Polyesters	p. 39
References	p. 39
3 Prepolymer Production	p. 41
3.1 Prepolymers	p. 41
3.1.1 Ease in Production	p. 42
3.1.2 Isocyanate Levels	p. 42
3.1.3 Structure of Polyurethane	p. 43
3.1.4 Reduction in Final Exotherm	p. 43
3.1.5 Easier Handling of Components	p. 43
3.1.6 Final Properties	p. 43
3.2 Laboratory Preparation	p. 44
3.2.1 Equipment	p. 44
3.2.2 Reactions	p. 46
3.2.3 Monitoring Reaction	p. 47
3.2.4 Prepolymer Storage	p. 48
3.3 Factory Preparation: Plant Production	p. 48
3.3.1 Safety	p. 48
3.3.2 Raw Material Storage	p. 50
3.3.3 Raw Material Preparation	p. 51
3.3.4 Reactor	p. 54
3.3.5 Nitrogen	p. 57
3.3.6 Heating/Cooling	p. 58
3.3.7 Process Control	p. 58
3.3.8 Vacuum	p. 60
3.3.9 Discharging Batch	p. 60
3.3.10 Quality Control and Assurance	p. 61
3.3.11 Typical Process	p. 63
3.4 Quasiprepolymers	p. 64
3.5 One Shot	p. 65
References	p. 65
4 Hand Processing	p. 67
4.1 Introduction	p. 67
4.1.1 Process Definition	p. 67
4.1.2 Importance of the Process	p. 67
4.1.3 Changes in Material Properties Before, During, and After Curing	p. 68
4.1.4 Stages of Curing and Factors Affecting Cure	p. 69
4.2 Introduction to Molding Process	p. 70
4.2.1 Prepare Mold	p. 72
4.2.2 Preheat Prepolymer	p. 72
4.2.3 Add Pigment or Other Additive	p. 72
4.2.4 Prepare Curative	p. 72
4.2.5 Mix Prepolymer and Curative	p. 73
4.2.6 Cast into Mold	p. 73
4.2.7 Trim Article and Fully Cure Molding in Oven	p. 74
4.3 Casting Health and Safety	p. 74
4.4 Mold Preparation	p. 75
4.4.1 Molds	p. 75
4.4.2 Cleaning and Repair	p. 76
4.4.3 Mold Release	p. 76
4.4.4 Assembly	p. 77
4.5 Batch Size Adjustment	p. 77
4.5.1 Quantity of Polyurethane	p. 77
4.5.2 Weight Calculations	p. 77
4.6 Prepolymers	p. 78
4.6.1 Calculations	p. 81
4.7 Pigments and Additives	p. 82
4.8 Curatives	p. 83
4.9 Degassing	p. 85
4.10 Mixing and Casting	p. 86
4.10.1 Premixing	p. 86
4.10.2 Curatives	p. 87
4.10.3 Mixing	p. 87
4.10.4 Casting	p. 88
4.11 Curing and Post Curing	p. 89
5 Processing	p. 91
5.1 Molding Methods	p. 91
5.1.1 Rotational Casting	p. 91
5.1.2 Centrifugal Casting	p. 92
5.1.3 Vacuum Casting	p. 92
5.1.4 Compression Molding	p. 93
5.1.5 Liquid Injection	p. 94
5.1.6 Complex Shapes	p. 94
5.2 Bonding	p. 94
5.2.1 Precasting	p. 94
5.2.2 Chemical Treatment	p. 95
5.2.3 Bonding Primer	p. 96
5.2.4 Casting and Curing of Bonded Prepolymer	p. 97
5.2.5 Postcasting	p. 97
5.3 Finishing	p. 98
5.3.1 Differences from Metals	p. 98
5.3.2 Machining Conditions	p. 99
5.3.3 Painting	p. 101
5.4 Plasticized Polyurethanes	p. 102
5.5 Epoxy-Polyurethane Blends	p. 103
6 Polyurethane Processing Problems	p. 105
6.1 Introduction	p. 105
6.2 General Problem Solving	p. 105
6.2.1 Low NCO Level	p. 105
6.2.2 Off Ratio	p. 105
6.2.3 High Exotherm	p. 107
6.2.4 Incorrect Temperature	p. 107
6.2.5 Curative Contamination	p. 108
6.2.6 Poor Mixing	p. 108
6.2.7 Casting Technique	p. 109
6.2.8 Dirty Molds	p. 110
6.2.9 Insufficient Cure	p. 110
6.2.10 Low Green Strength	p. 110
6.3 Ratios	p. 111
6.4 Bond Failure	p. 111
6.4.1 Bond Failures at the Metal-to-Primer Interface	p. 112
6.4.2 Bond Failures in the Polyurethane-Cement Interface	p. 112
7 Properties	p. 115
7.1 Introduction	p. 115
7.1.1 Type of Backbone	p. 115
7.1.2 Backbone Length	p. 115
7.1.3 Type of Isocyanate	p. 116
7.1.4 Ratio of Reactants	p. 116
7.1.5 Type and Concentration of Curative	p. 116
7.1.6 Final Processing Conditions	p. 117
7.2 Physical Properties	p. 117
7.2.1 Temperature	p. 117
7.2.2 Resilience	p. 118
7.2.3 Thermal Conductivity	p. 120
7.2.4 Stress-Strain Properties	p. 121
7.2.5 Hardness	p. 122
7.2.6 Tensile	p. 125
7.2.7 Tear	p. 125
7.2.8 Coefficient of Friction	p. 126
7.2.9 Compression Set	p. 126
7.2.10 Permeability to Water	p. 127
7.3 Environmental	p. 128
7.3.1 Thermal	p. 128
7.3.2 Ozone Resistance	p. 130
7.3.3 Hydrolysis	p. 130
7.4 Electrical	p. 131
7.5 Radiation	p. 134
7.6 Chemical	p. 134
7.6.1 Inorganic Chemicals	p. 134
7.6.2 Organic Chemicals	p. 136
7.7 Wear	p. 138
7.7.1 Abrasive Wear	p. 139
7.7.2 Erosive Wear	p. 140
References	p. 144
8 Applications	p. 145
8.1 Introduction	p. 145
8.2 Major Type and Grade Selection	p. 146
8.2.1 Hardness	p. 146
8.2.2 Tear Strength	p. 146
8.2.3 Temperature	p. 146
8.2.4 Heat Buildup	p. 146
8.2.5 Hydrolysis Resistance	p. 147
8.2.6 Compression Set	p. 147
8.2.7 Tensile Strength	p. 147
8.2.8 Oil Resistance	p. 147
8.2.9 Wear Resistance	p. 147
8.2.10 FDA Approval	p. 147
8.2.11 Flexibility in Adjustments to Formula	p. 148
8.2.12 Cost	p. 148
8.3 Polyurethane's Role in the Materials Field	p. 148
8.3.1 Comparison to Metals	p. 148
8.3.2 Advantages over Plastics	p. 149
8.3.3 Advantages over Rubber	p. 150
8.3.4 Limitations of Polyurethanes	p. 151
8.4 Polyurethane Selection Criteria	p. 151
8.4.1 Applications in Tension	p. 152
8.4.2 Load Bearing	p. 153
8.4.3 Applications in Shear	p. 155
8.4.4 Wear Resistance	p. 157
8.4.5 Vibration Damping	p. 158
8.4.6 Electrical	p. 158
8.5 Design	p. 159
8.5.1 Bonding	p. 159
8.5.2 Fillets	p. 159
8.5.3 Shape	p. 160
8.6 Summary	p. 161
9 Tools for Evaluation	p. 163
9.1 Introduction	p. 163
9.2 Verification of Selected Grade	p. 164
9.3 Quality Control Tests	p. 164
9.3.1 Weighing Equipment	p. 164
9.3.2 Temperature	p. 164
9.3.3 Linear Dimensions	p. 165
9.3.4 Density	p. 165
9.3.5 Hardness	p. 166
9.3.6 Curative Level	p. 167
9.3.7 Surface Porosity	p. 168
9.4 Type Tests	p. 169
9.4.1 Tensile Stress-Strain	p. 169
9.4.2 Set Tension Compression	p. 170
9.4.3 Tear Strength	p. 172
9.4.4 Adhesion	p. 173
9.4.5 Peel Tests	p. 174
9.4.6 Shear Tests	p. 175
9.4.7 Compression Modulus	p. 176
9.4.8 Shear Modulus	p. 177
9.4.9 Dynamic Mechanical Testing	p. 177
9.4.10 Resilience	p. 178
9.4.11 Dynamic Mechanical Analysis (DMA)	p. 180
9.4.12 Electrical Properties	p. 181
9.4.13 Environmental Resistance	p. 182
9.4.14 Chemical	p. 182
9.4.15 Heat Aging	p. 184
9.4.16 Fungal	p. 185
9.4.17 Wear Resistance	p. 185
9.4.18 Dynamic Heat Buildup	p. 187
9.5 Prototype and Service Tests	p. 187
9.5.1 First Part Evaluation	p. 188
9.5.2 Verification of Design	p. 188
9.5.3 Simulated Tests	p. 188
9.5.4 Field Trials	p. 189
9.6 Investigative Research	p. 189
9.6.1 Infrared Studies	p. 189
9.6.2 Gas Chromatography	p. 192
9.6.3 Nuclear Magnetic Resonance (NMR)	p. 192
9.6.4 X-Ray Diffraction	p. 192
9.6.5 Differential Scanning Calorimetry (DSC)	p. 192
9.6.6 Atomic Force Microscopy	p. 193
9.6.7 Scanning Electron Microscopy (SEM)	p. 193
9.6.8 High Performance Liquid Chromatography (HPLC)	p. 193
9.6.9 Size Exclusion Chromatography	p. 193
References	p. 194
10 Health and Safety	p. 195
10.1 Introduction	p. 195
10.1.1 Rationale	p. 195
10.1.2 Work Environment	p. 195
10.1.3 Acute Exposure	p. 196
10.1.4 Chronic Exposure	p. 196
10.2 The Workplace	p. 196
10.2.1 Information Sources	p. 196
10.3 Prepolymer Preparation	p. 199
10.3.1 Isocyanates	p. 199
10.3.2 Polyols	p. 199
10.3.3 Prepolymers	p. 200
10.3.4 Curatives	p. 200
10.3.5 Catalysts	p. 201
10.3.6 Other Additives	p. 202
10.3.7 Solvents	p. 203
10.3.8 Heat	p. 203
10.3.9 Products of Combustion	p. 204
10.4 Engineering	p. 204
10.4.1 Gases	p. 204
10.4.2 Machinery	p. 205
10.5 Material Safety Data Sheet Format	p. 207
References	p. 210
Appendix 1 Abbreviations and Trade Names	p. 211
Appendix 2 Polyurethane Curatives	p. 213
Appendix 3 Mold Release Agents	p. 215
Appendix 4 Technical Terms	p. 217
Appendix 5 Calculations	p. 227
Appendix 6 Isocyanate Calculation	p. 233
Appendix 7 Chemical Structures	p. 235
Appendix 8 Applications	p. 241
Index	p. 243

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