Evolution of hot strain induced crystalline texture of poly(ethylene terephthalate) films

Abstract

Differential scanning calorimetry, birefringence and X-ray poles figure analysis were used to characterize the evolution of the strain induced crystalline texture of poly(ethylene terephthalate) films. The films are initially wholly amorphous and drawn above the glass transition temperature. For a critical draw ratio, a crystalline phase appears with a weak crystalline fiber texture. For the highest draw ratio we observe that the texture is better defined, and the drawing tends to align the crystallites with the draw direction and to increase slightly the degree of crystallinity. For the highly drawn sample an extra texture is also observed.