Relationship between impulse breakdown and morphology of polyethylene

Many factors which influence electric breakdown characteristics of polyethylene have been discussed and reported. Some papers described the relationship between electrical tree and superstructure of polyethylene and emphasized that initial tree or electrical trees, which lead to electric breakdown, grow along the trans-crystal, or lamella, or boundaries of spherulites of low density polyethylene (LDPE) and high density polyethylene (HDPE). However, very few papers were reported from more micro point of view, such as the relationship between long period, amorphous condition, lamella or molecule orientation and electrical breakdown. In this paper, the authors emphasize the importance of the amorphous area of XLPE superstructure which influence the intrinsic electric breakdown and have investigated the relationship amorphous conditions and impulse properties.