The Effect of Strain History on the Crystallization Behavior of Bulk Poly(ethylene Terephthalate)

Abstract

The crystallization of bulk tensile samples of glassy, amorphous poly(ethylene terephthalate) was studied as a function of various deformation and annealing treatments. Per cent crystallinity, orientation function, crystallite size, and long period spacing were measured to characterize the samples. Crystallization, necking, and orientation occurred during straining when, at a given temperature, the strain rate was sufficient to generate a critical stress level within the material. During subsequent annealingcrystallization was nucleated by the crystallites formed during deformation. The observed behavior was consistent with a model proposed by Dismore and Statton for drawn nylon 66 yarns and which was previously discussed by Dumbleton for the case of poly(ethylene terephthalate).