1300 187 187
This book aims to rehabilitate kinetic modeling in the domain of polymer ageing, where it has been almost abandoned by the research community. Kinetic modeling is a key step for lifetime prediction, a crucial problem in many industrial domains in which needs cannot be satisfied by the common empirical methods.
The book proposes a renewed approach of lifetime prediction in polymer oxidative ageing. This approach is based on kinetic models built from relatively simple mechanistic schemes but integrating physical processes (oxygen diffusion and stabilizer transport), and use property (for instance mechanical failure) changes. An important chapter is dedicated to radiation-induced oxidation and its most important applications: radiochemical ageing at low dose rates and photo-chemical ageing under solar radiation. There is also a chapter devoted to the problem of ageing under coupled oxidation and mechanical loading.
| Acknowledgements | p. xi |
| General Introduction | p. xiii |
| Methodological Aspects | p. 1 |
| Definitions | p. 1 |
| Empirical and semi-empirical models | p. 4 |
| The Arrhenius model | p. 4 |
| The isodose model | p. 5 |
| The overall kinetic model | p. 6 |
| The correlation method | p. 6 |
| Various mathematical "laws" | p. 7 |
| Conclusion | p. 7 |
| Towards a non-empirical method of lifetime prediction | p. 8 |
| Principles | p. 8 |
| The multiscale model | p. 8 |
| A new philosophy of ageing | p. 10 |
| Arguments against kinetic modeling | p. 11 |
| Overcomplexity | p. 11 |
| Heterogeneity | p. 12 |
| Conclusion | p. 15 |
| Principles of model elaboration | p. 15 |
| Aspects Common to all Oxidation Processes | p. 17 |
| Oxidation: a radical chain mechanism | p. 17 |
| Radical nature | p. 17 |
| Chain reaction | p. 18 |
| Propagation | p. 20 |
| Propagation by addition to double bonds | p. 21 |
| Propagation by hydrogen abstraction | p. 22 |
| Propagation by P° radicals | p. 24 |
| Termination | p. 25 |
| The P° + P° termination | p. 26 |
| The P° + POO° termination | p. 28 |
| The POO° + POO° termination | p. 29 |
| Initiation | p. 30 |
| Polymer decomposition | p. 30 |
| Decomposition of oxidation products | p. 32 |
| Thermodynamic aspects | p. 41 |
| Initiation | p. 41 |
| Propagation | p. 42 |
| Termination | p. 43 |
| Basic Kinetic Schemes | p. 45 |
| Simplifying hypotheses | p. 45 |
| Hypothesis U: unicity of the reactive site | p. 45 |
| Hypothesis E: Oxygen excess | p. 47 |
| Hypothesis A: constant initiation rate | p. 47 |
| Hypothesis S: stationary state | p. 48 |
| Hypothesis C: constant substrate concentration | p. 48 |
| Hypothesis L: long kinetic chain | p. 49 |
| Hypothesis T: relation between the termination rate constants | p. 49 |
| Hypothesis H: homogeneity of reaction | p. 49 |
| Hypothesis B: "closed loop" scheme | p. 49 |
| The ASEC scheme | p. 50 |
| Towards an AEC scheme | p. 53 |
| The ASCTL scheme | p. 54 |
| The BESC scheme | p. 57 |
| Characteristics common to all BESC schemes | p. 58 |
| Unimolecular decomposition of hydroperoxides | p. 61 |
| Bimolecular decomposition of hydroperoxides | p. 63 |
| The BASC scheme | p. 66 |
| The unimolecular BASC model | p. 66 |
| Another approach to the BASC schemes | p. 69 |
| How are we to recognize the mechanisms? | p. 71 |
| Other schemes | p. 74 |
| Consumption of the substrate | p. 74 |
| Unsaturated substrates | p. 76 |
| Intramolecular propagation in polypropylene | p. 79 |
| Co-oxidation | p. 83 |
| General problems of kinetic analysis of polymer oxidation. The outlines of a new approach | p. 85 |
| Near-universality of the kinetic behavior | p. 86 |
| Rate constants | p. 88 |
| A systematic approach | p. 89 |
| Oxidation and Oxygen Diffusion | p. 93 |
| Properties of oxygen transport in polymers | p. 93 |
| Solubility | p. 93 |
| Diffusivity | p. 96 |
| The reaction/diffusion equation | p. 101 |
| Conventional approach | p. 101 |
| Numerical resolution | p. 107 |
| Thickness of the oxidized layer. Shape and evolution of the profile | p. 108 |
| Stabilization | p. 111 |
| Principles of stabilization | p. 111 |
| Action on [O2] | p. 112 |
| Action on radiation | p. 113 |
| Capture or destruction of radicals and hydroperoxides | p. 113 |
| Action on hydroperoxide decomposition | p. 113 |
| Hydroperoxide decomposers | p. 114 |
| Metal deactivators | p. 116 |
| Stabilization by capture of P° radicals | p. 117 |
| Carbon black | p. 117 |
| Nitroxide radicals | p. 118 |
| Stabilization by capture of POO° radicals | p. 119 |
| General | p. 119 |
| POO° radical scavengers | p. 121 |
| Synergistic mixtures HD + CBA | p. 125 |
| Polyfunctional stabilizers | p. 126 |
| Hindered amines | p. 127 |
| Mechanistic aspects | p. 127 |
| Kinetic aspects | p. 129 |
| Other stabilizing mechanisms | p. 131 |
| Physical aspects of stabilization by additives | p. 131 |
| Solubility | p. 132 |
| Volatility, evaporation | p. 135 |
| Diffusivity | p. 138 |
| Evaporation-diffusion | p. 141 |
| Demixing and other phenomena | p. 142 |
| Molecular Mobility and Reactivity | p. 145 |
| The issue | p. 145 |
| The chemical way | p. 149 |
| Example of application: oxidation of PE at low temperature | p. 151 |
| The physical way | p. 154 |
| Control by diffusion of macromolecular reactive species and heterogeneity | p. 158 |
| The paradox of thermostability in glassy polymers | p. 161 |
| Structural Changes Caused by Oxidation | p. 163 |
| On the molecular scale | p. 163 |
| Absorbed oxygen, oxygenated groups | p. 163 |
| Chemiluminescence | p. 164 |
| Volatile oxidation products | p. 166 |
| How are we to include the formation of the oxidation products in the kinetic model? | p. 169 |
| On the macromolecular scale | p. 175 |
| Scissions in linear polymers | p. 176 |
| Scissions in three-dimensional polymers | p. 182 |
| Simultaneous crosslinking and scissions | p. 187 |
| On the morphological scale | p. 192 |
| Amorphous polymers | p. 192 |
| Immiscible mixtures of amorphous polymers | p. 193 |
| Semi-crystalline polymers with a glassy amorphous matrix | p. 193 |
| Semi-crystalline polymers with a rubbery amorphous phase | p. 194 |
| Effects of Oxidation on Physical and Mechanical Properties | p. 203 |
| Introduction | p. 203 |
| Weight changes | p. 204 |
| Particular cases | p. 207 |
| Changes in density and volume | p. 207 |
| Optical properties | p. 210 |
| Changes in the refractive index | p. 210 |
| Coloration | p. 212 |
| Surface state | p. 214 |
| Quantifying the effects of oxidation on the optical properties | p. 215 |
| Electrical properties | p. 215 |
| Dielectrical spectrum | p. 215 |
| Dielectrical fracture | p. 217 |
| Glass transition and melting | p. 218 |
| Glass transition temperature | p. 218 |
| Melting point | p. 222 |
| Mechanical properties at low strains | p. 223 |
| Reminders | p. 223 |
| Elastomers, rubbery phases | p. 225 |
| Glassy amorphous phases | p. 226 |
| Semi-crystalline polymers | p. 229 |
| Fracture properties in the case of homogeneous degradation | p. 230 |
| Glassy and semi-crystalline amorphous linear polymers with a glassy amorphous phase undergoing degradation | p. 230 |
| Semi-crystalline polymers with a rubbery amorphous phase undergoing degradation | p. 234 |
| Elastomers undergoing degradation | p. 236 |
| Thermoset materials undergoing degradation | p. 238 |
| Effects of superficial oxidation on fracture behavior | p. 239 |
| Fracture properties in the case of homogeneous crosslinking | p. 243 |
| Glassy amorphous polymers | p. 243 |
| Elastomers | p. 245 |
| Couplings | p. 249 |
| Introduction | p. 249 |
| "Spontaneous" cracking | p. 250 |
| Coupling between cracking and oxidation | p. 252 |
| Lifetime under static strain and oxidation | p. 254 |
| Mechano-chemical initiation | p. 254 |
| Effect of oxidation on the fracture kinetics | p. 257 |
| Physical ageing and oxidation | p. 264 |
| Oxidation during processing - degradation and recycling | p. 266 |
| Thermoplastics | p. 266 |
| Thermoset materials | p. 274 |
| Oxidation Under Irradiation | p. 277 |
| Definitions. General aspects | p. 277 |
| Characteristics of radiation | p. 277 |
| Difference between photochemical and radiochemical initiation | p. 278 |
| Quantities characterization the radiation and interaction between the matter and the radiation | p. 279 |
| Quantities characterizing the reaction | p. 282 |
| Radiochemical initiation | p. 283 |
| A perculiarity of radiochemical ageing | p. 288 |
| Stabilization | p. 291 |
| Photochemical initiation | p. 291 |
| Initiation by photolysis of hydroperoxides | p. 292 |
| "Acceleration factor", linked to the intensity | p. 293 |
| Initiation by thermal and photochemical decomposition of POOHs | p. 294 |
| Initiation in an absorbent environment, thickness of the photo-oxidized layer | p. 295 |
| Initiation by other processes | p. 296 |
| Polychromatic light sources | p. 297 |
| Photostabilization | p. 300 |
| Stabilization by screen effect | p. 300 |
| Ageing under natural sunlight | p. 308 |
| Solar radiation at the earth's surface | p. 308 |
| Kinetics of polymer photo-ageing | p. 313 |
| Conclusion on photochemical ageing under natural solar radiation | p. 319 |
| Bibliography | p. 321 |
| Appendix | p. 347 |
| Index | p. 353 |
| Table of Contents provided by Ingram. All Rights Reserved. |
ISBN: 9781848213364
ISBN-10: 1848213360
Series: ISTE
Audience:
Professional
Format:
Hardcover
Language:
English
Number Of Pages: 356
Published: 5th March 2012
Dimensions (cm): 23.8 x 15.5
x 2.71
Weight (kg): 0.696
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