The Local Structure of Noncrystalline Polymers: An X-ray Approach

Abstract

he x-ray scattering from noncrystalline polymers is diffuse in nature and is often only used to classify a material as "amorphous." This contribution is concerned with detailing how useful structural information may be obtained from such diffuse scattering patterns. The techniques for obtaining reliable quantitative intensity data from noncrystalline polymers are outlined with particular emphasis upon the particular problems which have to be faced when dealing with organic material. A framework is introduced, within which we may begin to discuss usefully the local molecular arrangements of noncrystalline polymers. The statistical structure is partitioned into intrachain or conformational, orientational, and spatial interchain parameters. The procedures which initially employ the comparison of the experimental intensity data with scattering functions derived from molecular models, are described with reference to natural rubber. This is seen as a .1 typical" polymer system. More complex chemical configurations are considered. Both poly(a-methylstyrene) and the phenylene range of polymers appear to exhibit distinct and additional local correlations. The role of these special correlations within the general framework of noncrystalline polymers is discussed.