Studies of Concentrated Solution of Acrylonitrile Copolymer

I. Non-Newtonian Flow

Abstract

The viscosity of concentrated solutions of acrylonitrile copolymer having different molecular weight in different polymer concentration was measured under high shear stresses.
Log-log plots of viscosity against molecular weight indicate straight lines at a series of constant shear stress with slopes that decrease from 2.67 towards 1.40 with increasing shear.Log-log plots of viscosity against polymer concentration also indicate straight lines at a series of constant shear rate.
If these plots are extrapolated to the range of lower molecular weight or lower polymer concentration, it was found that these plots converged to a point. The point found experimentally is considered to be an entanglement transition point which was obtained from the measurements of zero-shear viscosity, as functions of molecular weights and polymer concentrations.
At the entanglement transition region, we have observed experimentally the following relationship between critical molecular weight and critical polymer concentration,
M^0.54C=K (constant)
where K is little affected by temperature.