The rheology of filled polymers

Abstract

The flow properties of polymer melts containing fillers of various shapes and sizes have been examined. If there is no failure of either the filler or polymer in the solid state, then the modulus enhancement for randomly distributed filler is equal to the melt viscosity enhancement under medium shear stress conditions (104 Nm−2) in simple shear flow or in oscillatory shear flow. Submicron‐size fillers, in particular, can form weak structures in the melt that greatly increase the low shear rate viscosity without changing the modulus of the solid proportionately. The highly pseudo‐plastic nature of polymer melts at shear stresses of 106 Nm−2 means that, even without orientation of filler particles toward the flow direction, the viscosity enhancement is less than at lower shear stresses. Copyright © 1971 John Wiley & Sons, Inc.