On the characterization of non-newtonian flow. II

Abstract

A new rheological method for the determination of the molecular weight distribution of polymers was developed using the critical viscosity for entanglement together with the Newtonian viscosity and the apparent viscosity at a shear stress in the non-Newtonian region. Alternately, two shear stresses in the non-Newtonian region may be used. It was established that the critical molecular weight for entanglement is independent of the shear stress but dependent on the shear rate.