Rheological and extrusion behavior of dispersed multiphase polymeric systems

摘要

AbstractAn experimental study of temperature effect and composition effect on the rheological and extrusion properties of several dispersed multiphase polymer melts were investigated, using a cone‐and‐plate rheometer and a capillary rheometer. The polymeric systems studied included three homopolymers (two polystyrenes and one poly(methyl methacrylate) (PMMA)), a mechanically blended copolymer of polystyrene and PMMA, two graft copolymers (rubber‐modified polystyrene and PMMA), and three particulate‐filled polystyrene (CaCO3, milled glass fiber, and glass flake). It was found that the principal normal stress difference plotted against shear stress gives rise to a temperature independence for all dispersed multiphase polymeric systems. Composition independent correlations, however, do not exist for the principal normal stress difference. The extrudate swell plotted against shear stress becomes independent of temperature only for the homopolymers and graft copolymers. For the mechanically blended polymers and particulate‐filled polymers, the temperature independent correlation does not exist. The reduction in viscosity of the glass fiber‐ and glass flake‐filled polystyrenes is found due to the degradation of the base polymer