High field conduction and carrier traps in polyethylene copolymerized with various monomers

Polyethylene (PE) has been widely used in the fields of wire and cable insulation because of its excellent electrical properties (low dielectric loss and high electric strength). Recently, the development of 500 kV class PE cable is in progress and the improvement of insulating materials is required to endure under a higher electric stress. Chemical modification (copolymerization, additives, etc.) and physical modification (morphology, crystallinity, etc.) of PE have been tried to increase its electric strength [1,2]. We found that electric strength of PE was improved by the copolymerization of monomers containing halogen atoms [3]. In order to clarify the role of halogen comonomers, in this paper, we have investigated high field conduction and carrier traps in PE copolymerized with various halogen comonomers.