Deformation and Fracture Behaviour of Polymer Materials (eBook)

Preface 6
Contents 8
List of Authors 21
Abbreviations 28
Modern Aspects of Fracture Mechanics in the Industrial Application of Polymers 32
1 Time-Dependent Fracture Behaviour of Polymers at Impact and Quasi-Static Loading Conditions 33
Abstract 33
1.1 Comparison of Methods for the Determination of R-Curves for Polymers at Impact Loading 34
1.2 Material Samples 35
1.2.1 Semicrystalline Polymers with Particle–Matrix Structure: PP/EPR/PE Copolymers 35
1.2.2 Short-Glass Fibre (GF)-Reinforced Semicrystalline Polymers: PP/GF 36
1.2.3 Nanophase-Separated Amorphous Polymers: Binary Blends of PS–PB Block Copolymers 37
1.2.4 CTOD Rate Under Quasi-Static Test Conditions: PP/EPR Blends 40
1.2.5 Influence of the Temperature: Amorphous Polycarbonate (PC) 41
1.3 Crack Propagation Kinetics of Polymers at Impact Loading Conditions 42
1.4 Discussion of Literature on Crack Propagation Kinetics 45
1.5 Stable Crack Propagation as Kinetic Phenomenon—An Outlook 49
References 50
2 Fatigue Crack Growth Behaviour of Epoxy Nanocomposites—Influence of Particle Geometry 52
Abstract 52
2.1 Introduction 52
2.2 Experimental 54
2.2.1 Materials 54
2.2.2 Preparation of Nanocomposites 55
2.2.3 Characterisation Methods 55
2.3 Results and Discussion 56
2.3.1 Organophilisation of Nanoparticles 56
2.3.2 Morphology 56
2.3.3 Fatigue Crack Propagation Behaviour 57
2.4 Conclusion 59
Acknowledgements 60
References 60
3 Fracture Mechanics Methods to Assess the Lifetime of Thermoplastic Pipes 62
Abstract 62
3.1 Failure Behaviour of Polymer Pipes 63
3.2 Fracture Mechanics Approach for Pipe Lifetime Calculations 65
3.3 Crack Growth in Polyethylene 68
3.4 Extrapolation to Static Crack Growth Behaviour from Fatigue Tests 70
3.5 Lifetime Calculation of PE Pipe Grades 73
3.6 Lifetime Calculation of a PE Pipe Grade at 80 °C Using Cyclic CRB Tests 74
3.7 Conclusion and Outlook 77
References 78
4 Thermographic Characterisation of the Deformation and Fracture Behaviour of Polymers with High Time and Spatial Resolution 84
Abstract 84
4.1 Introduction 84
4.2 Experimental 85
4.2.1 Materials 85
4.2.2 Methods 86
4.3 Results 88
4.3.1 Thermomechanical Characterisation of PET 88
4.3.2 Thermomechanical Characterisation of PC 94
4.4 Discussion 96
4.4.1 Polycarbonate—Affine Deformation with Uniform Energy Dissipation 97
4.4.2 Poly(Ethylene Terephthalate)—Localised Deformation and Complex Influence of Two Phases 97
4.5 Conclusion 100
References 100
5 Mechanical and Fracture Mechanical Properties of Polymorphous Polypropylene 102
Abstract 102
5.1 Introduction 102
5.2 Experimental Part 104
5.3 Results and Discussion 106
5.3.1 Degree of Crystallinity 106
5.3.2 Influence of Cooling Rate on the Resistance Against Stable Crack Initiation and Crack Growth 107
5.4 Conclusion 109
Acknowledgements 109
References 109
6 Numerical Modelling of Damage Initiation and Failure of Long Fibre-Reinforced Thermoplastics 111
Abstract 111
6.1 Introduction 111
6.2 Problem Formulation 112
6.2.1 Experimental Observation 112
6.2.2 Microscopic Observation 112
6.2.3 Numerical Microstructural Model 114
6.3 Numerical Results 115
6.3.1 Single-Fibre Unit Cell Under Uniaxial Tension 115
6.3.2 Unit Cells Containing Three Fibres 116
6.3.3 Variations of the Fibre Overlapping Length and Load Direction 118
6.4 Discussion 119
6.5 Summary 119
References 120
Advanced Structure-Sensitive Methods for Analysing Cracks and Fracture Surfaces 121
7 Characterisation of Polymers in the Scanning Electron Microscope—From Low-Voltage Surface Imaging to the 3D Reconstruction of Specimens 122
Abstract 122
7.1 Introduction 122
7.2 Low-Voltage Mode of the SEM 123
7.3 Low-Vacuum Mode of the ESEM 124
7.4 The ESEM Mode 127
7.5 Artefacts and Beam Damage 128
7.6 3D Information Using In Situ Ultramicrotomy 130
7.7 Conclusions 133
Acknowledgements 134
References 134
8 3D Reconstruction of Cracks in Polymers—New Insight into the Fracture Behaviour? 136
Abstract 136
8.1 Introduction 136
8.2 Preparation and Image Processing 138
8.3 Results and Discussion 139
8.4 Conclusion 144
References 145
9 Determination of the Stable Crack Growth by Means of the Fluorescence Adsorption-Contrast Method (3D-FAC Method) 147
Abstract 147
9.1 Introduction 148
9.2 Experimental 149
9.2.1 Materials 149
9.2.2 J-R-Curve Determination 150
9.3 Development of a Fluorescence Microscopy Procedure for ?a Measurement 151
9.3.1 Fluorescent Penetration Dye Colouring 151
9.3.2 Optimisation of the Fluorescent Application Process 152
9.3.3 Fluorescence Adsorption-Contrast Method (3D-FAC Method) 155
9.4 Results and Discussion 159
9.5 Conclusions 161
References 162
10 Acoustic Emission Analysis for Assessment of Damage Kinetics of Short-Glass Fibre-Reinforced Thermoplastics—ESEM Investigations and Instrumented Charpy Impact Test 165
Abstract 165
10.1 Introduction 166
10.2 Theoretical Background 167
10.2.1 Acoustic Emission (AE) Analysis 167
10.2.2 Frequency Analysis—Wavelet Transform (WT) 170
10.3 Experimental Details 171
10.3.1 In Situ Tensile Tests in ESEM Coupled with AE Measurement 171
10.3.2 Coupling ICIT and AE Analysis 173
10.4 Results 175
10.4.1 ESEM Investigations—Coupling the In Situ Tensile Test with AE Analysis 175
10.4.2 AE Measurements During ICIT 183
10.5 Summary 187
Acknowledgements 188
References 188
11 The Fractography as a Tool in Failure Analysis—Possibilities and Limits 191
Abstract 191
11.1 Introduction 191
11.2 Fractography—Fracture Surface Structures 192
11.2.1 Waves and Grid Lines 192
11.2.2 Fracture Parabola Respectively U- or V-Shaped Ramps 193
11.2.3 Ramps, Bars or Steps 195
11.2.4 Example: Fracture of a Multi-Layer Pipe 195
11.3 Limits of Validity of the Fractography for Filled and Reinforced Plastics 197
11.4 Summary 199
References 200
Fracture Mechanics and Related Methods for Analysing the Fracture Safety and Lifetime of Plastic Pipe Materials 201
12 Slow Crack Growth of Polyethylene—Accelerated and Alternative Test Methods 202
Abstract 202
12.1 Introduction 202
12.2 Slow Crack Growth 203
12.3 Test Methods to Determine Slow Crack Growth Behaviour of PE 203
12.3.1 Conventional Test Methods 203
12.3.2 Accelerated Test Methods: (Accelerated) Full Notch Creep Test (FNCT and aFNCT) 204
12.3.3 Alternative Test Methods: Strain Hardening Test (SHT) 207
12.3.4 Alternative Test Methods: Cracked Round Bar Test—CRB Test 210
12.4 Conclusions 211
References 212
13 Polypropylene for Pressure Pipes—From Polymer Design to Long-Term Performance 213
Abstract 213
13.1 Introduction PP Market Overview 213
13.2 Morphology and Polymorphism of PP 215
13.3 Short-Term Properties—Charpy and Pipe Falling Weight 216
13.4 From Microstructure to Final Properties 218
13.5 Influence of Processing 220
13.6 Long-Term Behaviour—Pressure Resistance and Slow Crack Growth in PP Materials 221
13.7 Conclusions 223
References 224
14 Lifetime of Polyethylene (PE) Pipe Material—Prediction Using Strain Hardening Test 226
Abstract 226
14.1 Introduction 226
14.2 Conventional Assessment of Long-Term Performance and Lifetime: The Pennsylvania Edge Notch Tensile Test and the Tensile Full Notch Creep Test 228
14.3 Accelerated Assessment of Long-Term Performance and Lifetime: The Strain Hardening Test 229
14.4 Results 230
14.5 Conclusions 232
Acknowledgement 233
References 233
15 Influence of Welding and Composition on the Short-Term Stable Crack Propagation Through Polyolefin Single- and Bilayered Structures 234
Abstract 234
15.1 Introduction 235
15.2 Experimental 235
15.2.1 Materials and Specimen Preparation 235
15.2.2 Equipment and Data Analysis 237
15.3 Results and Discussion 238
15.3.1 Influence of Specimens Shape, Orientation, Welding and Loading Speed on Stable Crack Initiation and Propagation Behaviour in Single-Layer Pipes Made from PE 100, PE 80 and PP Materials 238
15.3.2 Influence of Interlayers and Crack Propagation Direction on Stable Crack Initiation and Propagation Behaviour in Bilayer Pipes Made from PP Materials 243
15.4 Summary 247
Acknowledgements 249
References 249
16 Influence of Different Welding Conditions of Polyolefin Pipes on Creep Crack Growth 251
Abstract 251
16.1 Introduction 252
16.2 Welding of Polyolefin Pipes 252
16.3 Material Properties of the Welded Region 253
16.4 Numerical Model Description 255
16.5 Location of Crack Initiation 256
16.6 Stress Intensity Factors for Different Configurations 257
16.6.1 Influence of Material Inhomogeneity 257
16.6.2 Influence of the Weld Bead Radius 258
16.6.3 Influence of Different Weld Bead Shape 258
16.7 Crack Trajectories for Different Welds 260
16.8 Lifetime Prediction 261
16.9 Conclusion 261
Acknowledgements 262
References 262
17 Epoxy Modifications—A Novel Sealing Material for Rehabilitation of Pipe Joints 264
Abstract 264
17.1 Introduction 265
17.2 Experimental Section 266
17.3 Results and Discussion 268
17.4 Conclusion 272
Acknowledgements 273
References 273
Deformation Behaviour and Fracture Mechanics Characteristics of Polymer Films and Adhesive Systems 275
18 Approaches to Characterise the Mechanical Properties of Films and Elastomers 276
Abstract 276
18.1 Introduction 276
18.2 Experimental Opportunities of Mechanical Films and Elastomers Testing 277
18.2.1 Conventional Tensile and Notched Impact Test After ISO 8256 277
18.2.2 Instrumented Notched Tensile Impact Test 278
18.2.3 Instrumented Puncture Impact Test 279
18.2.4 Tear Test 280
18.2.5 Peel Tests 281
18.3 Examples of Use 283
18.3.1 Assessment of the Toughness Properties of Elastomers 283
18.3.2 Influence of Chemical Loading on the Mechanical Properties of a Thermoplastic Film 284
18.3.3 Influence of Chemical Loading on the Toughness Properties of Elastomers 285
18.3.4 Evaluation of a PE/PB-1 Peel System 286
18.4 Conclusions 288
References 288
19 Fracture Mechanics Characterisation of Peelfilms 290
Abstract 290
19.1 Introduction 291
19.2 Experimental 293
19.3 Results and Discussion 295
References 299
20 Fracture Mechanics Characterisation of Low-Adhesive Stretch Films 301
Abstract 301
20.1 Introduction 302
20.2 Experimental 304
20.2.1 Material and Composition of the Films 304
20.2.2 Cling Test According to ASTM D 5458 305
20.3 Results and Discussion 309
20.4 Conclusion 313
References 313
21 Thermal Stability and Lifetime Prediction of an Epoxide Adhesive System 315
Abstract 315
21.1 Introduction 315
21.2 Materials and Methods 317
21.2.1 Material and Samples 317
21.2.2 Spectroscopic Techniques and Mechanical Analyses 317
21.2.3 T-Peel Test and Tensile Lap-Shear Test 318
21.3 Results and Discussion 318
21.3.1 Thermomechanical Analysis 318
21.3.2 ATR-IR Spectroscopy 319
21.3.3 Raman Spectroscopy and Thermogravimetric Analysis 322
21.3.4 Lifetime Prediction: T-Peel Test and Tensile Lap-Shear Test 322
21.4 Conclusions 327
References 327
Fatigue Crack Propagation, Lifetime and Long-Term Mechanical Behaviour of Thermoplastics and Elastomers 330
22 Morphology and Fatigue Behaviour of Short-Glass Fibre-Reinforced Polypropylene 331
Abstract 331
22.1 Introduction 331
22.2 Analysis of Morphology of SFRP 332
22.3 Determination of Fatigue Behaviour 339
References 347
23 Characterisation of the Deformation and Fracture Behaviour of Elastomers Under Biaxial Deformation 351
Abstract 351
23.1 Introduction 351
23.2 Concept of the Biaxial Test Stand 352
23.3 Upgrading of a Biaxial Testing Method 354
23.3.1 New Clamping System for High Biaxial Deformation 355
23.3.2 Specimen Geometry 356
23.3.3 Crack Propagation with the New Specimen 357
23.4 Material 357
23.5 Results 358
23.5.1 Material Behaviour Under Biaxial Load 358
23.5.2 Strain Amplification at the Crack Tip of a SENT Sample 359
23.5.3 Crack Propagation Under Biaxial Load 360
23.5.4 Crack Propagation and Estimation of the Tearing Energy 361
23.6 Conclusion 364
References 364
24 Influence of Thermal Ageing Process on the Crack Propagation of Rubber Used for Tire Application 366
Abstract 366
24.1 Introduction 366
24.2 Theoretical Background 369
24.2.1 Dynamic-Mechanical Analysis (DMA) 369
24.2.2 Fracture Crack Growth (FCG) 370
24.3 Experimental Details 371
24.3.1 Material Preparation 371
24.3.2 Ageing 371
24.3.3 DMA 372
24.3.4 FCG 372
24.4 Results and Discussion 373
24.4.1 DMA 373
24.4.2 FCG 375
24.5 Conclusion 377
Acknowledgements 377
References 378
25 Development of Magnetorheological Elastomers (MREs) for Strength and Fatigue Resistance 380
Abstract 380
25.1 Introduction 381
25.2 Preparation of Materials 383
25.3 Experimental Methodology 384
25.4 Results and Discussion 386
25.5 Summary and Conclusions 388
Acknowledgements 389
References 389
26 Fibre-Reinforced Polyamides and the Influence of Water Absorption on the Mechanical and Thermomechanical Behaviour 391
Abstract 391
26.1 Introduction and Objectives 392
26.2 Experimental 392
26.2.1 Materials 392
26.2.2 Experimental Procedure 393
26.3 Results and Discussion 394
26.3.1 Water Absorption 394
26.3.2 Dynamic-Mechanical Analysis (DMA) 395
26.3.3 Monotonous Tensile Tests 396
26.3.4 Media Creep Tests 399
26.4 Summary and Outlook 401
References 402
27 Accelerated Measurement of the Long-Term Creep Behaviour of Plastics 403
Abstract 403
27.1 Introduction 403
27.2 Principle of the Stepped Isothermal Method 405
27.3 Creep Testing Using SIM 406
27.4 Construction of a Master Curve 409
27.5 Assessment of the Method 411
27.6 Applications of SIM 412
27.7 Conclusions 414
References 415
Influence of Ageing on Mechanical and Fracture Mechanics Performance of Thermoplastics and Elastomers 417
28 Hygrothermal Ageing of Injection-Moulded PA6/GF Materials Considering Automotive Requirements 418
Abstract 418
28.1 Introduction 418
28.2 Material and Experiments 420
28.3 Results and Discussion 421
28.4 Summary and Conclusion 429
References 430
29 Ageing of Polymer Materials—Testing, Modelling and Simulation Considering Diffusion 433
Abstract 433
29.1 Introduction 433
29.2 Test Method 435
29.2.1 Change in Stiffness Over a Long Period of Time 435
29.2.2 Diffusion 435
29.3 Mechanical Model and Numerical Application 437
29.4 Computational Results 438
29.4.1 O-Ring Application 438
29.4.2 Compression Test Specimen—Surface–Volume Ratio 438
29.5 Conclusions and Discussion 440
Acknowledgements 440
References 441
30 Investigations of Elastomeric Seals—Low-Temperature Performance and Ageing Behaviour 442
Abstract 442
30.1 Introduction 442
30.2 Behaviour at Low Temperatures 443
30.3 Methodology for the Ageing of Elastomeric Seals 446
30.4 Conclusion 453
References 453
Mechanical Properties and Fracture of Elastomers—Influence of Composition, Reinforcement and Crosslinking 455
31 Mechanical Reinforcement in a Polyisoprene Rubber by Hybrid Nanofillers 456
Abstract 456
31.1 Introduction 456
31.2 Experimental 458
31.3 Results and Discussion 460
31.3.1 Transmission Electron Microscopy Analyses 460
31.3.2 Mechanical Behaviour 461
31.4 Conclusions 467
References 467
32 Structure–Property Correlations of SSBR/BR Blends 469
Abstract 469
32.1 Introduction 470
32.2 Experimental 470
32.3 Results 472
32.3.1 Influence of the Composition on the Processing-Related Properties 472
32.3.2 Influence of Composition of the Rubber Mixture on the Physical Properties 475
32.3.2.1 Influence of Silane Type and Content on the Mechanical and Fracture Mechanical Properties 475
32.3.2.2 Influence of the TROVO®Powder Content on the Mechanical Properties 476
32.4 Structure–Property Correlation 478
32.5 Conclusions 480
Acknowledgements 481
References 481
33 Comparison Between Peroxide and Radiation Crosslinking of Nitrile Rubber 482
Abstract 482
33.1 Introduction 482
33.2 Experimental 484
33.2.1 Materials and Samples Preparation 484
33.2.2 Radiation Crosslinking 484
33.2.3 Peroxide Thermal Crosslinking 485
33.2.4 Crosslink Density Determination 485
33.2.5 Chain Scission and Crosslinking Ratio Determination 486
33.2.6 Mechanical Properties Test 487
33.3 Results and Discussion 487
33.4 Conclusion 489
References 489
34 Wood Flour as a Filler of Natural and Epoxidised Natural Rubber 491
Abstract 491
34.1 Introduction 491
34.2 Materials and Methods 492
34.2.1 Materials 492
34.2.2 Sample Preparation 492
34.2.3 Testing Methods 493
34.3 Results and Discussion 493
34.3.1 Effect of Wood Flour Derived from Coniferous Trees (CF) on Properties of NR and ENR 493
34.3.2 Effect of Wood Flour Derived from Deciduous Coniferous Trees (DF) on Properties of NR and ENR 495
34.4 Conclusion 497
References 497
35 Characterisation of the Ultimate Tensile Properties of Elastomers by a Dimensionless Hooke Number—A New Approach to Failure Envelopes 498
Abstract 498
35.1 Introduction 498
35.2 Theoretical Background 499
35.3 Experimental Part 502
35.3.1 Selection of Polymers and Recipes of Test Compounds 502
35.3.2 Mixing Procedure, Crosslinking and Testing 502
35.4 Results and Discussion 503
35.5 Summary and Conclusions 510
Acknowledgements 510
References 511
36 Thermomechanical Analysis Strategies for Elastomer Components Under Dynamic Loading 512
Abstract 512
36.1 Introduction and Overview 512
36.2 Simultaneous Solution Scheme 514
36.3 Sequential Solution Scheme 516
36.4 Conclusion and Outlook 520
Acknowledgements 521
References 521
37 Influence of Selected Silica Fillers on the Properties of Vulcanised Rubber Blends 522
Abstract 522
37.1 Introduction 522
37.2 Materials and Methods 523
37.3 Results and Discussion 524
37.4 Conclusion 529
Acknowledgements 529
References 529
Index 531