A concise, self-contained introduction to solid polymers, the mechanics of their behavior and molecular and structural interpretations. This updated edition provides extended coverage of recent developments in rubber elasticity, relaxation transitions, non-linear viscoelastic behavior, anisotropic mechanical behavior, yield behavior of polymers, breaking phenomena, and other fields.

Mechanical properties of solid polymers

Recent attempts have been made to assess the relative merits of the free volume and entropy theories of viscous flow in glass‐forming liquids by accurate measurement of viscosity over wide temperature ranges, and subsequent comparison with the equations derived from these theories. In the author's view, this effort is misguided. The theories are crude and qualitative, and such tests are too stringent. It is better to make qualitative or semiquantitative comparison of a wide variety of physical phenomena; judged by this criterion, the entropy theory appears more successful. It is conjectured that further progress can be made by accepting the crude, naive character of any model we are likely to find tractable for the foreseeable future, and recognizing both the values and limitations of such models. A picture of the flow process in viscous liquids is proposed, in an attempt to answer certain questions about the molecular steps in flow either answered unsuccessfully or ignored by present theories, in the hop...

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Viscous Liquids and the Glass Transition: A Potential Energy Barrier Picture

The field of enthalpy relaxation is reviewed. Current phenomenologies for dealing with the non-linear and non-exponential character of enthalpy relaxation are presented, and their successes and shortcomings are discussed. Qualitative experimental data and quantitative parameterizations are summarized, and some directions for future research are suggested.

Enthalpy relaxation and recovery in amorphous materials

https://www.umsl.edu/~chickosj/JSCPUBS/dsccal.pdf

Reference materials for calorimetry and differential thermal analysis

Transition vitreuse dans les polymères amorphes. Etude phénoménologique

The effect of pressure on glass temperature and dielectric relaxation time of polyvinyl acetate

Thermal Properties of Atactic and Isotactic Polystyrene

THE thermally induced transition of solvated poly-γ-benzyl-L-glutamate (PBG) molecules from a helical to a random coil configuration has been the subject of recent investigations1–3. Similar transitions, brought about by temperature or by other changes, occur in several poly-amino-acids4, and the general phenomenon has been treated theoretically by a number of authors5.

Thermal Helix-coil Transition in Poly-γ-benzyl-L-glutamate

The enthalpy of denaturation of lysozyme was determined by measuring the heat, capacity of an aqueous solution of this protein in the vicinity of the transition temperature, 46 °C at pH 1. Within experimental error the calorimetric, heat (56 ± 8 kcal/mole) was found to agree with the van't Hoff transition enthalpy (63 ± 6 kcal/mole) determined from optical rotation measurements as a function of temperature. This indicates that denaturation of this protein can be interpreted in terms of a two-state model. Successive measurements of the same sample showed, from several lines of evidence, that the transition was about 80% reversible for the particular environmental conditions and thermal history involved in the study.

Heat of denaturation of lysozyme

The effects of deuteration and of changes in solvent composition on the thermo dynamics of the helix–coil transition have been studied by calorimetric and optical measurements in the poly-γ-benzyl-L-glutamate–dichloroacetic acid–1,2-dichloro-ethanc system. For a given solvent composition, deuteration of the polypeptide and of the acid lowers the transition temperature Tc, while an increase in the volume fraction of acid in the solvent raises Tc. A rise in Tc is accompanied by a decrease in both the van't Hoff and the calorimetric heats of transition, but at different rates. The result is a temperature dependency in the Zimm-Bragg cooperation parameter σ. Possible causes of this result and its implications are discussed.

J. M. O'Reilly

Papers

The effect of pressure on glass temperature and dielectric relaxation time of polyvinyl acetate

Thermal Properties of Atactic and Isotactic Polystyrene

Thermal Helix-coil Transition in Poly-γ-benzyl-L-glutamate

Heat of denaturation of lysozyme

Deuteration and solvent composition effects in the helix–coil transition of poly‐γ‐beiizyl‐L‐glutamate