Recovery of polymer blends after melt elongation: Analysis of a model for small and large capillary numbers

Abstract

Applying an effective medium approximation, we theoretically investigate the recovery of binary blends of immiscible polymers after melt elongation. In our model, we consider effective values for the Hencky strain rates of the disperse and the matrix phase. We derive temporal evolution equations which allow calculation of the transient recovered stretch. Numerical solutions of this set of equations are presented and discussed. Our analysis reveals that the capillary number strongly influences the recovery process. By comparing the predictions of our model with experiments, we show that our model captures the basic features of the experimental data, i.e. the time scale of the recovery process and the equilibrium value of the recovered stretch.