Electrical Properties of 10MeV Electron Beam Irradiated and Aged Low Density Polyethylene

Polymers play a very important role in electrical systems as insulation materials. The microscopic failures occurring in the polymer under working conditions will be important in its required characteristics. In this work we focused on the effects of accelerated aging on the electrical properties of low density polyethylene (LDPE) and crosslinked polyethylene (XLDPE). The samples of LDPE were prepared in sheet form with the thickness of 0.6 +/- 0.1mm and were irradiated under the 10MeV electron beam of a Rhodotron accelerator at the dose range of 70 to 370kGy. Then, the samples were stored in an oven at temperature 75 degrees C for 3, 6, 10 and 13 days. Electrical properties such as the breakdown voltage and resistance of the aged samples were measured and compared. Increasing the aging time for unirradiated samples has a serious and moderate influence on their surface resistivity and breakdown voltage, respectively. The results indicated a maximum value for the surface resistance at the optimum radiation absorbed dose, which is approximately 220kGy for all the samples.