A Comprehensive Expression for Temperature Dependence of Liquid Viscosity

Abstract

A simple emprical expression for temperature dependence of liquid viscosity, which carries two adjustable parameters and includes a glass transition temperature, Tg, and the liquid viscosity ηg at Tg, has been proposed in the form: log(η/ηg)=A[exp{B(Tg-T)/T}-1] This expression has been applied to 14 liquids including polymeric materials. The mean values of A and B for 11 substances are found to be 15.29±1.04 and 6.47±1.13, respectively. The Andrade equation and the Williams-Landel-Ferry equation for liquid viscosity can be derived analytically from the proposed equation with reasonable approximation. © 1988, The Society of Rheology, Japan. All rights reserved.