Structural transformations in polyethylene irradiated at elevated temperature

Using X-ray diffraction method within big and small angles, the structure of high density polyethylene irradiated at 100 deg by the doses 5 to 1500 Mrad, has been studied. It was shown that within the dose interval 5 to 300 Mrad the radiation is accompanied by the growth of big period, intensity of the small-angle reflex, the sharp growth of the crystallites demension along the direction (110). The observed growth of intensity of the small-angle reflex is explained by the growing of the crystallites dimensions and, at the same time, by the decrease of the amorphous phase density that is stipulated for a fixation of a high temperature structure by crosslinks under the radiation and has a character of a radiative annealing. Within the doses interval 300 to 1500 Mrad the irradiation leads to the total fracture of the crystalline structure