CONNECTION BETWEEN THRESHOLD YIELD STRESS AND DOUBLE YIELD IN SEMI-CRYSTALLINE POLYMERS

摘要

In conclusion, a simple model including viscoelastic elements is extended from the linear viscoelastic range to describe stress- strain behaviour of HDPE; the results demonstrate that double yielding is intimately related to the existence of a threshold yield stress at high temperatures and low strain rates. The fit could clearly be improved both by including the anelastic component and by introducing a more appropriate expression for the effect of strain on mobility.