ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
A continuum rheological theory, endowed with generalized structural significance, has recently been developed. Based on nonequilibrium thermodynamics, it relates stress σ, strain rate \documentclass{article}\pagestyle{empty}\begin{document}$\dot \varepsilon$\end{document} and temperature in terms of material evolution through a series of structural states. The theory has previously had success in dealing with crystalline metals and surface physics, and here it is applied to crosslinked rubbery polymers in the nominally amorphous condition. Structure is believed to be related to interchain associations, chain entanglements, chain ends, and other defects in the hypothetical ideal network which by itself would lead to neo-Hookean predictions in uniaxial deformation, σnH ∝ λ2 - λ-1, where λ is the stretch ratio. Predictions are made for σ(λ) in both tension and compression and shown to be more compatible with data than either σnH(λ) or the Mooney - Rivlin expression σMR(λ). Only two parameters are required, moduli Go (reflecting initial structure) and Gs (the steady-state condition), and rate effects are incorporated through Go(\documentclass{article}\pagestyle{empty}\begin{document}$\dot \varepsilon$\end{document}) and Gs(\documentclass{article}\pagestyle{empty}\begin{document}$\dot \varepsilon$\end{document}). The phenomena of yielding and stress softening in cyclic tensile loading are also predicted, suggesting advantages to this approach relative to conventional viscoelastic continuum models.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1985.180231102
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