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Non‐Newtonian flow and the steady‐state shear compliance
Author(s) -
Prest W. M.,
Porter Roger S.,
O'Reilly J. M.
Publication year - 1970
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.1970.070141104
Subject(s) - viscoelasticity , newtonian fluid , steady state (chemistry) , thermodynamics , polymer , shear flow , flow (mathematics) , rheology , capillary action , viscosity , shear (geology) , molar mass distribution , materials science , shear rate , mechanics , chemistry , physics , composite material
A survey of viscoelastic data on amorphous polymer melts indicates that the steady‐state shear compliance, J e , of many systems can be approximated from a knowledge of their flow response. For systems with monomodel molecular weight distributions, the absolute value of the reduced complex viscosity, η * /η 0 , is found to equal 0.67 ± 0.03 at the frequency ω, where ωη 0 J e = 1. This result applies to a variety of polymer systems and to a wide range of molecular weights and distributions as long as the highest molecular weight dispersion of the distribution constitutes more than 20 weight per cent of the sample. This relationship determines J e from non‐Newtonian flow data and thus provides a consistent way to relate differently shaped reduced variable curves and to calculate compliances from characteristic times reported in the literature. The connection between some commonly used times and J e is given. The method of calculating J e is successfully applied to capillary measurements of melt viscosities and to characteristic times determined from steady‐state shear measurements of concentrated polymer solutions.