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 degreesC, -25 degreesC, and 90 degreesC are indications of the gamma-, beta-, alpha -transition, respectively, and a new, formerly unknown peak at about 50 degreesC will be attributed to the space charge relaxation. The RMA data showed that compensation temperature (T-c) and degree of disorder increased with increasing the gamma -ray intensity and decreasing antioxidant content, whereas the compensation time (tau (c)) decreased. It can be concluded that the cooperative molecular motion in LDPE system becomes more active as the gamma -ray intensity increases and antioxidant content decreases. (C) 2001 Elsevier Science Ltd. All rights reserved.