On the Relaxation Mechanism of Semi-Crystalline Polymers in the Glass-Leather Transition

Abstract

The relaxation mechanism of semi-crystalline polymers in the glass-leather transition i.e., the second order transition has not yet so far been understood so well as that of amorphous polymers in the glass-rubber transition is.
In this paper, the authors have tried to extend the theoretical approaches usually made in explaining the relaxation mechanism of amorphous polymers to the study of that of semi-crystalline polymers, in other words, the existence of crystalline phase has been taken as the potential effects upon the amorphous chain and as a factor reforming the term of entropy elasticity.
So far as the theoretical consideration is concerned, the authors have used Bueche Model and solved the problem in the light of the theory that accounts for the vibration of a string.
The relaxation spectra of polyethylene terephthalates having several degrees of crystallinity have been decided from the measurement of complex dynamic tensile modulus on the hypothesis of time-temperature superposition within the glass-leather transition region, and compared with the theoretical results proposed.