Thermally stimulated current study in γ-ray irradiated low density polyethylene

Thermally stimulated current and relaxation map analysis (RMA) were used to characterize the low temperature transition of low density polyethylene (LDPE). Four current peaks were observed. The peaks at about −125°C, −25°C, and 90°C are indications of the γ-, β-, α-transition, respectively, and a new, formerly unknown peak at about 50°C will be attributed to the space charge relaxation. The RMA data showed that compensation temperature (Tc) and degree of disorder increased with increasing the γ-ray intensity and decreasing antioxidant content, whereas the compensation time (τc) decreased. It can be concluded that the cooperative molecular motion in LDPE system becomes more active as the γ-ray intensity increases and antioxidant content decreases.