Quantitative X-Ray Studies of Order in Amorphous and Crystalline Polymers

Abstract

The application of a Geiger counter spectrometer to the quantitative study of the scattering from amorphous and crystalline polymers has been investigated, and this technique has been shown to be very well suited to this purpose. The experimental technique used is described. The following polymers have been studied, in order to gain some insight into the structure and order characterizing the amorphous and crystalline regions : hexadecane, polyisobutylene, natural rubber, polystyrene (oriented and unoriented), polymethyl methacrylate, polytrifluorochloro ethylene, octacosane, polyethylene, polytetrafluoroethylene, and various natural keratins. The scattering patterns are analyzed for their structural implications. It has been found that the x-ray diffraction patterns of polystyrene and polymethyl methacrylate change as these materials are heated through and above the region of their second-order transi tion. It is shown that these changes are interpretable in terms of definite changes in structure of the polymeric chains. The bearing of these results on the nature of the glass transition in these materials is discussed.