Analysis of flow data on molten polymers

Abstract

On the basic assumption that viscosity is a continuous function of shear rate it is deduced that any non-Newtonian fluid should conform to a flow equation of the form ν = ν∞+ ν0−ν∞ 1+aD n where η is the viscosity at shear rate D, η 0 and η ∞ are limiting values at respectively zero and infinite rate of shear, and α is a constant. With a value of 2 3 for the index η the equation is applied successfully to published data on both polystyrene and polyethylene melts. An analysis by Bingham (I) in which the non-Newtonian flow of polymer melts is attributed solely to elasticity is shown to be inadequate.