MOLECULAR-ORIENTATION ANGLE OF BIAXIALLY STRETCHED POLY(ETHYLENE-TEREPHTHALATE) FILMS

The orientation behaviors of a commercially produced poly(ethylene ter ephthalate) film were investigated. The in-plane angular distributions of the overall, crystalline and amorphous orientation were determined using various techniques. The in-plane orientation angle was defined by the angle between the direction of the maximum distribution and the transverse direction (TD) of the film sample. It was found that both the crystalline and amorphous in-plane orientation angles varied with position of the TD, whereas there was no detectable variation in the o rientation factors of the crystalline phase. From the dynamic viscoela stic test, it was also observed that the angle of the maximum storage modulus was closer to the orientation angle of amorphous chains than t hat of crystallites. (C) 1997 Elsevier Science Ltd.