Polymer Fracture

ISBN-13: 9783642964626 / Angielski / Miękka / 2012 / 332 str.

H. -. H. Kausch

Opis

This book on "Polymer Fracture" might as well have been called "Kinetic Theory of Polymer Fracture." The term "kinetic theory," however, needs some de finition or, at least, some explanation. A kinetic theory deals with and particu larly considers the effect of the existence and discrete size, of the motion and of the physical properties of molecules on the macroscopic behavior of an ensemble, gaseous or other. A kinetic theory of strength does have to consider additional aspects such as elastic and anelastic deformations, chemical and physical reactions, and the sequence and distribution of different disintegration steps. In the last fifteen years considerable progress has been made in the latter do mains. The deformation and rupture of molecular chains, crystals, and morphologi cal structures have been intensively investigated. The understanding of the effect of those processes on the strength of polymeric materials has especially been furthered by the development and application of spectroscopical methods (ESR, IR) and of the tools offracture mechanics. It is the aim of this book to relate the conventional and successful statistical, parametrical, and continuum mechanical treatment of fracture phenomena to new results on the behavior of highly stressed molecular chains.

Spis treści

1 Deformation and Fracture of High Polymers, Definition and Scope of Treatment.- References.- 2 Structure and Deformation.- I. Elements of the Superstructure of Solid Polymers.- A. Amorphous Regions.- B. Crystallites.- C. Superstructure.- D. Characterization.- II. Deformation.- A. Phenomenology.- B. Molecular Description.- III. Model Representation of Deformation.- References.- 3 Statistical, Continuum Mechanical, and Rate Process Theories of Fracture.- I. Introduction.- II. Statistical Aspects.- III. Continuum and Fracture Mechanics Approach.- A. Classical Failure Criteria.- B. Fracture Mechanics.- C. Continuous Viscoelastic Models.- IV. Rate Process Theories of Fracture.- A. Overview.- B. Eyring’ Theory of Flow.- C. Tobolsky-Eyring.- D. Zhurkov, Bueche.- E. Hsiao-Kausch.- F. Gotlib, Dobrodumov et al.- G. Bueche-Halpin.- References.- 4 Strength of Primary Bonds.- I. Covalent Bonds.- A. Atomic Orbitals.- B. Hybridization.- C. Molecular Orbitals.- D. Multiple Bonds.- II. Bond Energies.- A. Electronie Energy and Heat of Formation.- B. Binding Energy of Exited States and Radicalized Chains.- 1. Electronic Excitation.- 2. Ionization.- 3. Radicalization.- III. Form of Binding Potential.- References.- 5 Mechanical Excitation and Scission of a Chain.- I. Stress-Strain Curve of a Singie Chain.- A. Entropy Elastic Deformation.- B. Energy Elastic Chain Deformation.- C. Non-Equilibrium Response.- II. Axial Mechanical Excitation of Chains.- A. Secondary or van der Waal’s Bonds.- B. Static Displacements of Chains Against Crystal Lattices.- C. Thermally Activated Displacements of Chains Against Crystal Lattices.- D. Chain Displacements Against Randomly Distributed Forces..- E. Dynamic loading of a chain.- III. Deexcitation of Chains.- References.- 6 Identification of ESR Spectra of Mechanically Formed Free Radicals.- I. Formation.- II. EPR Technique.- A. Principles.- B. Hyperfine Structure of ESR Spectra.- C. Number of Spins.- III. Reactions and Means of Identification.- IV. Assignment of Spectra.- A. Free Radicals in Ground High Polymers.- B. Free Radicals in Tensile Specimens.- References.- 7 Phenomenology of Free Radical Formation and of Relevant Radical Reactions (Dependence on Strain, Time, and Sample Treatment).- I. Radical Formation in Thermoplastics.- A. Constant Rate and Stepwise Loading of Fibers.- B. Effect of Strain Rate on Radical Production.- C. Effect of Temperature.- 1. Apparent Energy of Bond Scission.- 2. Rate of Bond Scission.- 3. Concentration at Break.- D. Effect of Sample Treatment.- II. Free Radicals in Stressed Rubbers.- A. Preorientation, Ductility, and Chain Scission.- B. Cross-Link Density, Impurities, Fillers.- III. Mechanically Relevant Radical Reactions.- A. Transfer Reactions.- B. Recombination and Decay.- C. Anomalous Decay.- D. Radical Trapping Sites.- References.- 8 The Role of Chain Scission in Homogenous Deformation and Fracture.- I. Small-Strain Deformation and Fracture of Highly Oriented Polymers.- A. Underlying Problems.- B. Loading of Chains before Scission.- C. Spatially Homogeneously Distributed Chain Scissions.- D. Formation of Microcracks.- E. Energy Release in Chain Scission.- F. Fatigue Fracture of Fibers.- G. Fractography.- II. Deformation, Creep, and Fatigue of Unoriented Polymers.- A. Impact Loading.- B. Failure under Constant Load.- C. Homogeneous Fatigue.- 1. Phenomenology and Experimental Parameters.- 2. Thermal Fatigue Failure.- 3. Wöhler Curves.- 4. Molecular Interpretations of Polymer Fatigue.- D. Yielding, Necking, Drawing.- E. Elastomers.- III. Environmental Degradation.- References.- 9 Molecular Chains in Heterogeneous Fracture.- I. Fracture Mechanics.- A. Stress Concentration.- B. Subcritical Crack Growth.- C. Critical Energy Release Rates.- II. Crazing.- A. Phenomenology.- B. Craze Initiation.- C. Molecular Interpretation of Craze Propagation and Breakdown.- D. Response to Environment.- III. Molecular and Morphological Aspects in Crack Propagation.- A. Fracture Surfaces.- B. Notched Tensile and Impact Fracture.- C. Fatigue Cracks.- D. Mechano-Chemistry.- References.- Appendix Table A—1. List of Abbrevations of the Most Important Polymers.- Table A—2. List of Abbrevations not Referring to Polymer Names.- Table A—3. List of Symbols.- Table A—4. Conversion Factors.