Experiments on Charge Generation in Cross-linked Polyethylene and Ethylene-Propylene Copolymer

Abstract

To study the space charge generation in cross-linked polyethylene (XLPE) and ethylene propylene copolymer (EPR), space charge profiles in both materials are measured using PEA method. The experimental results demonstrated that a big difference was discovered in the detected charge profiles between XLPE and EPR. We discovered that the diffusion of charge is significantly faster in EPR than in XLPE. The authors confirmed that the negative hetero-charge is generated near the positive electrode in EPR when moisture are coexisting with acetophenone. The effects of antioxidants on the generation of hetero-space charges in XLPE and EPR are also studied using XLPE and EPR samples containing different kinds of phenolic and sulfur type antioxidant. The authors discovered that hetero-charge is generated in XLPE and EPR containing sulfur type, or sulfur-containing phenolic, antioxidant when acetophenone are existing in the material. The hetero-charge generation is inferred to be caused by the combined effect between acetophenone and the component containing sulfur atoms of the antioxidants.