Abstract
Viscosities of concentrated solutions of acrylonitrile-methyl acrylate copolymers (methyl acrylate contents in copolymers were 3-5%) in dimethyl formamide were measured by a rotational viscometer (so-called B-type viscometer).The stability of the solution was examined viscometrically under various conditions of dissolution.The stable and molecular-dispersed solutions of this polymer does not show much increase in viscosity with time.The effect of rate of shear upon the viscosity of solution can be written as follows:is the rpm of viscometer and k and n are constants. It has been found that the different values of viscosity were obtained for various types of polymers of the same Mn. The relationship between viscosity and concentration of the solution, temperature and molecular weight of polymer can be expressed respectively as follows:1.(The influence of the concentration of the solution)2.(The influence of molecular weight of polymer)3.(The influence of temperature)The apparent activation energy of flow is not constant but varies with the concentration of the solution and with the molecular weight of the polymer.
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