The dynamic behavior and stress relaxation of polymer melts

Polymer melts exhibit a decrease in apparent viscosity as a function of decreasing time scale of shearing. In order to obtain an understanding of the mechanisms giving rise to this non‐Newtonian behavior studies have been made of the dynamic linear viscoelastic response, the limit of linear viscoelastic behavior and the stress relaxation in polymer melts after steady state shearing. The results of these experiments are analyzed with respect to shear induced changes in the relaxation spectrum and the effect of these changes on the apparent viscosity.