Theoretical consideration of the effect of crystallinity on the viscoelastic properties of polyethylene

Ferry's reduction is applicable to amorphous polymers, but there is no reduction corresponding to Ferry's available for crystalline polymers. Here will be proposed a method of reduction based on a simple mechanical model, with the degree of crystallinity and draw ratio as its parameters. Confirmation of this method was attained from the stress relaxation curve of polyethylene for a draw ratio equal to 1. In this case, we have only to use log E + log T 0 / T − log Λ/(1 + Λ), log t − (ε/ k ) (1/ T − 1/ T 0 ) + log T / T 0 instead of log E , log t , where, Λ is the degree of crystallinity and ε′ the term corresponding to the activation energy of viscosity. A satisfactory master curve was obtained. The master curve due to frequency change could be obtained in the same way; however, this has not yet been confirmed, there being no appropriate data.