A theory of viscosity of dilute and moderately concentrated polymer solutions |
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Authors: | VP Budtov |
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Institution: | “Plastpolymer” Okhta Research and Production Association, Polyustrovski; pr. 32, 195108 Leningrad, U.S.S.R. |
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Abstract: | A model theory of viscosity η for moderately concentrated polymer solutions is based on the assumption of a “local viscosity” effect and intermolecular hydrodynamic and thermodynamic interactions. It is shown that η is given by where γ is 0–0.4 and depends on the quality of the solvent, a varies between 0,4 and 0.8 and depends on the fraction of the “free volume” of the systems, H0 is the activation energy of the solvent and π is the polymer volume concentration. The dependence of η and “activation energy” of π and T for various molecular weights and qualities of solvents is described quantitatively. Anomalous dependences of η] and of η on M for low polymer are obtained. An expression for η is proposed: where K is the Huggins-Martin coefficient and F(π) = 1 for most solutions when T is > Tg. For poor solvents the H vs c curve (where H is the activation energy of η of solution) has a minimum value at moderate concentrations. For good solvents, H depends slightly on the molecular weight according to an empirical equation: Expressions are given from the viscosities of solutions of miscible and also solutions of immiscible polymers. |
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