An electron paramagnetic resonance study of LDPE irradiated with high-energy electron beam

Cross-linking of the polyethylene was performed with a high-energy electron beam. Electron paramagnetic resonance spectroscopy was used to study the lifetime of unpaired electron in the irradiated samples. Time-dependent electrical parameters are investigated for the cross-linked low-density polyethylene. Both dielectric constant and dielectric strength almost remained unchanged, but for short times, the volume resistivity and loss factor increased and decreased, respectively. It is predicted that for lifetime longer than 48 h, the electrical parameters were constant. It is believed that the variation of some electrical properties during time is due to the effects of trapped electrons.