VISCOSITY MODEL FOR POLYDISPERSE POLYMER MELTS

A simple superposition model was used to define the relationship betwe en molecular weight distribution and shear viscosity for linear polyme ric systems. Gel permeation chromatography data for molecular weight d istributions were fitted using statistical distribution functions. A s imple superposition model was then employed to calculate the shear vis cosity for the systems investigated. The effect of polydispersity on t he shape of the flow curves was calculated. The simplicity of the mode l makes feasible its use in numerical simulations of complex geometrie s as encountered in polymer processing equipment. The present study al so sheds some light on the relationship between entanglement and disen tanglement phenomena in polymeric systems. (C) 1998 The Society of Rhe ology.