The Effect of Crosslinking on the Electrical Properties of LDPE

Conference poster, 2009

Two low density polyethylene (LDPE) grades with varying vinyl content were crosslinked with partly different mechanisms. The electrical tree inception voltage, using a double needle setup, was measured on the two materials when crosslinked with increasing amounts of peroxide. The morphology changed from fully developed spherulites to more or less randomly distributed lamella stacks with increasing density of the crosslinked network. A gradual decrease in crystallinity was also noted. It was found that the increasing network density with the subsequent changes in morphology and crystallinity had a major effect on the tree inception voltage. In the densely crosslinked networks sometimes no trees were observed after visual inspection, although the test equipment indicated a tree. There were no significant differences between the two materials.