Crystallinity of Saran

II. Crystallinity measured by X-Ray Diffraction Method

Abstract

In the previous paper, the crystallinity of Saran filament was calculated from density measurements. This paper reports on crystallinity calculations from X-ray diffraction measurements. In the X-ray diffraction pattern of Saran filaments, it is impossible to distinguish precisely the crystalline part from the amorphous part, so a simple method was used. To avoid any error due to the orientation of the filament, finely cut samples are placed at random position perpendicular to the X-ray beam and the field rotated. The crystallinity of non-heat-treated filamentsi s 25.4%w hich increases up to 30.6% by stretching to maximum stretch ratio under heat-treatment. The crystallinity has a tendency to increase slowly with the increase of stretch ratio, but increases rapidly with the increase of temperature of the cooling bath. Therefore, the results measured by density method and X-ray method agree in that the crystallinity changes with changes of the conditions of the extrusion and heat-treatment.