Abstract
This paper describes the relationship between the superstructure of polymer, blending low density polyethylene (LDPE) and high density polyetylene (HDPE), and tree intiation. We have observed the superstructure (lamella and spherulite) of blended polyethylene using a transmission electron microscope and a polarizing microscope, and investigated relation between blending ratio of LDPE and HDPE and tree initiation voltage. As a result, when HDPE was blended from 5% to 40%, tree initiation voltage raised. In order to find the cause of this rise in voltage, we have continuously observed crystallization of blended polyetylene through a polarizing microscope. When temperature falls from melting point, first at 120°C HDPE spherulites were formed. Then, at 100°C the LDPE spherulites were produced in conjunction with HDPE spherulites. At this time, trans-crystal yielded between both spherulites, and bonded LDPE spherulites and HDPE spherulites. Trans-crystal strongly bonded at spherulite borders which were electrically weak and, raised the tree initiation voltage
