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Non‐Newtonian flow of concentrated solutions of high polymers
Author(s) -
Onogi Shigeharu,
Kobayashi Tadashi,
Kojima Yasuhiro,
Taniguchi Yoshishige
Publication year - 1963
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.1963.070070305
Subject(s) - polymer , thermodynamics , intrinsic viscosity , shear rate , viscometer , viscosity , relative viscosity , newtonian fluid , reduced viscosity , volume fraction , polystyrene , chemistry , materials science , polymer chemistry , analytical chemistry (journal) , chromatography , physics , organic chemistry
Abstract Non‐Newtonian flow of moderately concentrated solutions of polyvinyl alcohol (PVA) in water and polystyrene (PS) in toluene were measured with a Maron‐Krieger‐Sisko viscometer at various temperatures and concentrations. The usual dependences of the apparent and zero shear viscosities for two polymers on rate of shear, temperature, and molecular weight have been found. The log‐log plot of zero‐shear viscosity versus concentration can be represented by two straight lines intersecting at one point (critical concentration c c ). The critical concentration in volume fraction of polymer, v 2c , multiplied by the chain length Z is not constant but decreases with decreasing Z , although it has the same order of magnitude as the value of Z c v 2 obtained from the log‐log plots of viscosity versus Z for many systems of polar and nonpolar polymers. The product c c ρ Z 1/2 (ρ = density of the solution) is constant and independent of Z . To explain the constancy of this product, an equivalent sphere model is presented. When the volume fraction of spheres is assumed to be unity, the extension of molecules agrees very well with the unperturbed extension evaluated from intrinsic viscosity data in ⊖ solvent.