Modeling of deformation behavior and strain-induced crystallization in poly(ethylene terephthalate) above the glass transition temperature

A constitutive model for large deformation stress-strain behavior and strain-induced crystallization in poly(ethylene terephthalate), at temperatures above the glass transition temperature, is proposed. In this model, the intermolecular resistance is treated in a composite framework where the crystalline and amorphous phases are considered as two separate resistances coupled through two different analog representations leading to the upper and the lower bound approaches. The crystallization rate is expressed following a non-isothermal phenomenological expression based on the modified Avrami equation. Our predicted results are compared to existing experimental results and good agreement is found. (C) 2003 Elsevier Ltd. All rights reserved.