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The steady flow shear modulus of polymer melts
Author(s) -
Blyler L. L.,
Huseby T. W.
Publication year - 1966
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1966.070100105
Subject(s) - viscoelasticity , shear modulus , materials science , thermodynamics , shear rate , rubber elasticity , strain rate , modulus , composite material , shear flow , shear (geology) , polymer , natural rubber , shear stress , rheology , physics
Relaxation times of polyethylene melts have been measured by Aloisio, Matsuoka, and Maxwell. One implication regarding their observations is that the elastic properties of polymer melts must be time‐dependent. In particular, the steady‐flow shear modulus depends on the strain rate. Some interpretations of data in the literature have been based on concepts in rubber elasticity where the steady‐flow modulus is an equilibrium value, independent of strain rate. We have used Pao's theory for viscoelastic flow together with measurements of relaxation times to discuss the strain rate dependence of the steady‐flow shear modulus of melts. The existence of a strain rate‐dependent shear modulus leads naturally to a nonlinear relation between shear stress and recoverable shear strain. The conclusions regarding the molecular weight dependence of the modulus also differ from interpretations based on rubber elasticity.