Rheological master curves of crystallizing polymer mixtures

Abstract

We present a simple methodology for extending linear viscoelastic measurements of crystallizing polymers to the high-frequency regime, where usually crystallization kinetics represents an obstacle. The idea is to perform rapid quenches, below the melting temperature (which corresponds to the high-frequency region), account for the thermal equilibration and the very slow early stages of crystallization, and perform the measurements before really crystallization sets in, in the "quasi-equilibrium" state. Albeit tedious, when properly done, this method works remarkably well, as demonstrated for a particular polybutadiene mixture, and opens the route for obtaining rheological master curves in a wide variety of crystallizing polymers. © Appl. Rheol.