LINEAR VISCOELASTIC PROPERTIES OF EPOXY-RESIN POLYMERS IN DILATATION AND SHEAR IN THE GLASS-TRANSITION REGION .1. TIME-TEMPERATURE SUPERPOSITION OF CREEP DATA

Measurements have been made of the creep compliance in dilatation and shear for an epoxy resin polymer, over a range of temperature spanning the glass transition region. Both compliances may be measured on the same specimen. The creep curves were superposed, and smooth composite curves were obtained both in dilatation and in shear. The WLF equation provides an adequate fit over the temperature range for which it is generally used. Shear creep data over a wide temperature range could be described by the Arrhenius equation, where the activation energy, ΔH, has a higher value above Tg than below Tg. For shear creep ΔH = 58 Kcal/mole for T < Tg, ΔH = 165 Kcal/mole for Tg < T. For creep in dilatation ΔH = 210 Kcal/mole. © 1979.