Abstract
Crystalline polymers such as polyethylene and polypropylene have been widely used in power cable and power condenser because of their high electrical strength and low dielectric loss. The spherulites would be formed on the cooling manufacture process of these polymeric materials. It is known that electrical insulation performance of the polymeric material is influenced by spherulites. However, the influence of spherulites, spherulite distribution and annealing on tree initiation is not entirely distinct so far.
In this paper, isotactic polypropylene film is used. Three kinds of samples were made that spherulite distribution is different. And then tree initiation voltage was measured. Crystallinity and crystal structure are studied by Infrared Spectrophotometer and X-Ray Diffractometer, respectively. The Effects of space charge, internal strain and spherulite permittivity on the tree initiation are discussed. The influence of spherulite, spherulite distribution and annealing on tree initiation is made known.
