SMALL-ANGLE X-RAY-SCATTERING STUDY OF ULTRA-HIGH-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE) GAMMA-IRRADIATED IN BULK

The effect of gamma irradiation on the structure of ultra-high molecul ar weight poly(ethylene oxide) (UHMWPEO) has been investigated by smal l-angle x-ray scattering (SAXS). The pressed and irradiated polymer po ssesses quite strong diffuse scattering. That fact makes the direct de termination of the main structural parameters very difficult. To solve the problem a modification of the standard evaluating methods is sugg ested. Thus, the separation of the porous scattering from that of stru ctural formations of PEO becomes possible. The application of a collim ation correction according to Schmidt's method enables to separate dif fuse and discrete parts in the scattering. Dependences of the long per iod, the gyration radii, and the difference between densities of cryst alline and amorphous phases on the irradiation dose show that the irra diation increases the density of amorphous areas. A packing of the lam ellar aggregates and increase of the porous sizes are observed.