Behaviour of Poly (vinyl alcohol) at High Temperatures

II. On the Small Angle Scattering of X-Ray By Ichiro Sakurada* and Yasuhiko Nukushina

Abstract

Small angle scattering intensity of poly (vinyl alcohol) was measured at high temperatures in order to obtain a knowledge of the long period in the direction of fibre axis, and was interpreted by the theory proposed by K. Hess and H. Kiessig. When heat-treated PVA fibres are heated under tension, keeping a constant length, the long period of 212Å at room temperature remains unchanged up to 225°C. Meanwhile the small angle scattering intensity increases. This is the case also for the heating without tension. For the fibres which have never been heat-treated, the long period increases from 111Å to 147Å on heating from room temperature to 225°C under tention and a remarkable increase in small angle scattering intensity is observed. The effect of heating on the long period and small angle scattering intensity is not so remarkable if no tension is applied during the heating process. In all cases, by cooling from a high temperature the long period does not vary whereas the intensity is lowered.