CRYSTALLITE SIZE DISTRIBUTION AND THE LATTICE-DISTORTIONS IN HIGHLY GAMMA-IRRADIATED LINEAR POLYETHYLENE

Crystallite size distributions and lattice distortions have been analysed for highly γ-irradiated linear polyethylene in the direction normal to 〈1 1 0〉 and 〈0 0 1〉 lattice planes through X-ray line profile analysis. It has been found that the lateral crystallite size is little affected irradiation greater than 1000 Mrad, whereas that in the chain direction decreases almost linearly with the dose of irradiation. A minor difference in the crystallite size between irradiation atmospheres, i.e. irradiation in air or in vacuum, has been disclosed at a very high dose of irradiation. The above degradation behaviour of crystallites and the change in lattice distortions have proved that radiation cross-links are mainly formed in the amorphous region near the lamellar surface of polyethylene. © 1979 Chapman and Hall Ltd.