Abstract: The annealing behaviour of irradiated polyethylene(PE) single crystals was studied with Mixed-Crystals IR spectroscopy, SAXS, WAXD and DSC. The results were: (1)There are both adjacent reentry folding and random stems in the PE single crystals, the former is predominant. (2)In the annealing below or at 90℃, reptation is the major molecular motion, and it leads to improvement of the crystal structure to limited extent; partial fusion and recrystalization are involved in the annealing at 105℃. (3)The crosslinking and damage in the crystal region caused by irradiation prevents the PE crystals from being improved.

Key words: polyethylene, deuterated polyethylene, irradiation, infrared, annealing