Wood-polymer composites

Kristiina Oksman Niska,Mohini Sain,Institute of Materials, Minerals, and Mining.9781420076110, 1420076116, 9781845692728, 1845692721

Wood-polymer composites (WPC) are materials in which wood is impregnated with monomers that are then polymerized in the wood to tailor the material for special applications. The resulting properties of these materials, from lightness and enhanced mechanical properties to greater sustainability, has meant a growing number of applications in such areas as building, construction and automotive engineering. This important book reviews the manufacture of wood-polymer composites, how their properties can be assessed and improved and their range of uses. After an introductory chapter, the book reviews key aspects of manufacture, including raw materials, manufacturing technologies and interactions between wood and synthetic polymers. Building on this foundation, the following group of chapters discusses mechanical and other properties such as durability, creep behavior and processing performance. The book concludes by looking at orientated wood-polymer composites, wood-polymer composite foams, at ways of assessing performance and at the range of current and future applications. With its distinguished editors and international team of contributors, Wood-polymer composites will be a valuable reference for all those using and studying these important materials.

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Table of contents :
Cover Page……Page 1
Related titles……Page 3
Title: Wood–polymer composites……Page 4
ISBN 978-1845692728……Page 5
Contents……Page 6
Contributors contact details……Page 12
Introduction……Page 15
1.1 Introduction……Page 16
Molecular structure……Page 17
Molecular organization……Page 19
1.2.2 Properties……Page 22
Wood anatomy……Page 25
Chemical constituents……Page 26
1.3.2 Sources and production of fillers and reinforcements from wood……Page 28
Density……Page 30
Moisture sorption……Page 31
Durability properties……Page 32
Thermal properties……Page 33
Mechanical properties……Page 34
1.5 References and further reading……Page 35
2.1 Introduction……Page 38
2.2 Lubricants and rheology control additives for thermoplastic composites……Page 41
2.3 Coupling agents……Page 44
2.4.1 Antioxidants……Page 46
2.4.3 PVC heat stabilizers……Page 47
2.5 Fillers……Page 48
2.7 Biocides……Page 51
2.8 Product aesthetics additives……Page 52
2.9 Flame retardants and smoke suppressants……Page 53
2.11 Conclusion……Page 55
3.1 Introduction……Page 56
3.2 The interface and interphase in composites……Page 57
3.3 Wetting, adhesion and dispersion……Page 58
3.3.2 Electrostatic bonding……Page 60
3.3.4 Interdiffusion……Page 62
3.4.1 Surface analysis……Page 63
3.4.2 Microscopy……Page 66
3.4.3 Single fibre pull-out and microbond tests……Page 69
3.4.4 Single-fibre fragmentation test……Page 71
3.4.5 Interfacial studies using laser Raman spectroscopy……Page 72
3.4.6 Other techniques……Page 73
3.5 Improving interface interactions in wood-polymer composites……Page 75
3.5.2 Improved interactions using additives……Page 76
3.6 Interphase effects on other properties……Page 81
3.7 Conclusions……Page 83
3.8 References and further reading……Page 84
4.2 Raw material handling……Page 87
Bulk materials: polymer……Page 89
4.2.2 Feeding systems……Page 90
Loss-in-weight feeding……Page 91
Belt feeder……Page 92
4.3 Compounding technologies……Page 94
4.3.1 Hot cold mixers……Page 95
4.3.3 Counter-rotating twin screw……Page 97
4.3.4 Corotating twin screw……Page 98
Modular construction for an optimised processing section……Page 99
4.4.1 Strand pelletising……Page 105
4.4.2 Hot face pelletising……Page 106
Underwater pelletiser……Page 107
Water ring pelletiser……Page 108
Dry cutting systems……Page 109
4.6 Injection moulding……Page 110
4.6.1 Standard injection with pre-compounded wood polymer composites……Page 111
4.6.2 In-line compounding……Page 112
4.7.1 Roll stack……Page 113
4.7.2 Double belt press……Page 114
4.9 References……Page 115
5.2.1 Anisotropic nature of wood fibers and role of polymer……Page 116
5.2.2 Interfacial shear strength and fiber length……Page 118
Flexural strength and modulus……Page 119
Tensile strength……Page 120
Impact resistance……Page 121
Hardness and dent resistance……Page 122
Fastener holding strength……Page 123
5.4.1 Effect of filler and polymer……Page 124
5.4.2 Optimization of mechanical properties of wood–polymer composites: interfacial modification……Page 128
5.6 References……Page 131
6.1 Introduction……Page 133
6.2 Elastic properties……Page 134
6.2.1 Material microstructure……Page 135
6.2.2 The in-plane Young’s moduli……Page 138
6.2.3 Micromechanical modelling for stiffness prediction……Page 140
6.2.4 Approach to determine the reinforcement efficiency of wood fibres……Page 144
6.3 Hygroexpansion……Page 146
6.3.1 Free deformation due to change in moisture content……Page 147
6.3.2 Approach to determine the hygroexpansion of wood fibres……Page 148
6.4 Strength……Page 149
6.4.1 Empirical models……Page 150
6.4.2 Interfacial effects……Page 151
6.6 References……Page 153
Weathering……Page 157
Biological attack……Page 158
7.2.2 Polymers……Page 159
7.3.1 Moisture effects……Page 160
Thermal expansion……Page 164
7.3.3 Weathering……Page 165
Decay……Page 167
Insects and marine borers……Page 169
Fiber modification……Page 170
7.4.2 Thermal changes……Page 171
Additives……Page 172
7.4.4 Biological attack……Page 175
7.5 Future trends……Page 176
7.7 References and further reading……Page 177
8.1 Introduction……Page 181
Linear viscoelasticity……Page 182
Non-linear creep……Page 188
8.2.2 Experimental methods……Page 189
8.3 Creep in wood–plastic composites……Page 191
Effect of the wood filler/fiber concentration……Page 192
Effect of the temperature……Page 193
Long-term creep and the time–temperature superposition (TTS) principle……Page 194
8.3.2 Interfacial adhesion……Page 196
8.4.1 Effect of the applied load……Page 198
8.5 Conclusions and future trends……Page 200
8.6 References……Page 201
9.1 Introduction……Page 205
9.2.1 Dry blending and mixing……Page 206
Alternative melt blenders and pelletizers……Page 207
9.3 Rheology of a wood fiber filled thermoplastic……Page 208
9.3.1 Influence of formulation components on the rheology of wood–polymer composites……Page 209
9.3.2 Importance of rheology on product quality of wood–polymer composites……Page 211
9.4.1 Ouput rate……Page 212
9.4.2 Extrusion melt pressure……Page 213
9.4.3 Extrusion parameter influences on composite properties……Page 216
Density……Page 217
Flexural properties……Page 218
Water sorption……Page 220
9.5 References……Page 222
10.2 Orientation of polymers……Page 223
Ram extrusion……Page 224
Polypropylene……Page 225
Drumsticks……Page 227
Hardwood flooring……Page 228
Low-density wood–polymer composites……Page 230
10.4 Current developments……Page 234
Inorganic fillers……Page 235
Reactive fillers……Page 237
Applications……Page 239
10.6 References……Page 240
11.1.1 Significance of wood–polymer composite foams……Page 242
11.1.3 Processing methods for wood–polymer composite foams……Page 243
11.2 Structure and characterization of wood–polymer composite foams……Page 244
11.3.2 Degradation and volatile emissions released from wood fiber……Page 246
11.3.3 Increased melt viscosity……Page 247
11.3.4 Critical processing temperatures and control of residence time……Page 249
11.4.1 Phase changes in foaming of wood–polymer composites……Page 250
Polymer/gas solution formation……Page 252
Cell growth control……Page 253
11.5.1 Chemical blowing agents: endothermic and exothermic……Page 254
11.5.2 Foaming of wood–polymer composites with chemical blowing agents in extrusion……Page 257
11.5.3 Foaming of wood–polymer composites with chemical blowing agents in injection molding……Page 258
11.6.1 Physical blowing agents……Page 259
11.6.3 Foaming of wood–polymer composites with physical blowing agents in extrusion……Page 260
11.7 Foaming of wood–polymer composites with heat expandable microspheres……Page 264
11.9 Effects of additives on wood–polymer composite foams……Page 265
11.9.1 Talc……Page 266
11.10 Summary and future trends……Page 267
11.11 References……Page 268
12.1 Introduction……Page 272
12.2 Performance measures and building codes……Page 274
12.3 Wood–polymer composite properties……Page 275
12.4 Building construction applications……Page 280
12.4.1 Product opportunities……Page 281
12.5 Conclusions……Page 285
12.6 References……Page 286
13.1 Introduction: comparing wood–polymer and glass-fiber reinforced polypropylene car door panels……Page 288
13.2.1 The data collection……Page 289
13.2.2 Modeling life-cycle assessment……Page 290
13.3.2 Functional unit and system boundaries……Page 291
13.3.3 Sources of data……Page 292
Wood fiber (mechanical pulp)……Page 293
13.3.5 Use phase……Page 294
13.3.8 Impact assessment methods……Page 295
13.4.1 Use of energy……Page 297
13.4.3 Major air pollutants……Page 298
13.5.1 Production of fiber……Page 300
13.5.3 End of life……Page 301
13.5.4 Life-cycle comparisons of the panels……Page 303
Climate change……Page 304
13.6.1 Sensitivity analysis……Page 306
Incineration and use of recycled materials……Page 307
Influence of different impact assessment methods……Page 308
13.7 The possible effect of the European Union legislation on the end-of-life vehicles……Page 310
13.8 Conclusions……Page 311
13.10 References……Page 312
14.1 Introduction……Page 315
14.2 The development of the European market: the example of Germany……Page 316
14.3 The most significant wood–polymer composite products in the European market……Page 319
14.3.2 Automobiles……Page 321
14.3.3 Furniture manufacturing……Page 322
14.3.5 The appearance of wood–polymer composite products……Page 323
14.4 Future – trends markets……Page 324
14.5 Future trends: processing and materials……Page 326
14.5.1 Interviews with different experts……Page 330
14.6 Conclusions……Page 331
14.7.1 Standardisation and quality……Page 332
Pro-K – industrial association semi-finished products and consumer products made from plastics eV (Industrieverband Halbzeuge und Konsumprodukte aus Kunststoff eV)……Page 334
14.7.3 List of the most important German/European producers……Page 335
14.8 The nova-Institut and Innovationsberatung Holz & Fasern……Page 337
14.8.1 Innovationsberatung Holz & Fasern……Page 339
14.9 Examples of wood polymer composite products……Page 340
14.10 References……Page 344
15.1 Introduction: wood–polymer composite decking……Page 346
Polyethylene-based products……Page 347
15.3.1 Mechanical performance……Page 348
15.3.2 Thermal expansion–contraction……Page 352
15.3.3 Shrinkage……Page 354
15.3.4 Slip resistance……Page 356
15.3.5 Water absorption, swell, buckling……Page 357
15.3.6 Microbial degradation……Page 358
15.3.7 Termite resistance……Page 360
15.3.8 Flammability……Page 361
15.3.9 Oxidation and crumbling……Page 362
15.3.10 Photo-oxidation and fading……Page 365
15.4 Conclusions……Page 367
15.5 References……Page 368