Influence of morphology on tree growth in polyethylene

It is well known that electrical trees are greatly influenced by the morphological structure in semi-crystalline materials. In this paper, samples of polyethylene films, including low-density polyethylene (LDPE) and high-density polyethylene (HDPE) have been re-crystallized by two kinds of different ways: natural cooling and quenching. The growth rate and the length of electrical trees were measured under the various conditions. It was found that electrical trees in HDPE grow easier than that in LDPE, even though HDPE is of high crystallinity and large spherulites size and show high resistance in tree initiation. It was presumed that the morphology is of different effects on the tree initiation and growth.