Microsecond Analysis of Quasi-Smectic Fibrillar Structure in the Continuous Fiber Drawing of Poly(ethylene terephthalate)

Abstract

Structure devpelopment in the continuous laser-drawing process of poly(ethylene terephthalate) fibers was investigated with a time resolution of 0.2 ms by real time synchrotron X-ray diffraction and fiber temperature measurements. The (001′) and (003′) reflections of a quasi-smectic fibrillar structure were observed from 0.16 ms after necking, and the reflection intensity reached a maximum at around 0.3 ms after necking, when the elastic energy stored at the necking had been released. The d-spacing of the (001′) reflection decreased with increasing time, and the quasi-smectic fibrillar structure had a length of 70 nm and a radius of 7.0 nm. The crystallization induction time and crystallization rate were 0.3 ms and 1100 s–1 based on the fiber temperature profile and 0.6 ms and 1400 s–1 based on the equatorial reflection intensity profiles. In the azimuthal intensity profile under the 2θ/θ arrangement, a single meridional peak of the (003′) plane was observed, and it is considered that the quasi-smectic fibrillar structure oriented uniaxially along the fiber axis with an orientation factor of 0.986.