Excellent DC Electrical Performance of a Byproduct-free Crosslinked Polyethylene Copolymer Blend for High-Voltage Cables

The byproducts of crosslinked polyethylene (XLPE) for high-voltage cables reduce the purity of the insulation, thereby limiting its DC electrical performance. The byproduct-free click chemistry reaction between polyethylene copolymers demonstrates significant potential as an alternative to peroxide crosslinking. In this paper, polyethylene copolymer blends were prepared, and their thermal properties, chemical composition, crystalline structure and dielectric characteristics were evaluated comprehensively. A low-density polyethylene and the resulting XLPE for high voltage cables were selected as references. In addition, the effect of antioxidant on the structure and properties of polyethylene copolymer blends was explored. The results show that the polyethylene copolymer blends exhibit superior DC electrical performance owing to the higher density of deep traps. The incorporation of polar groups in the copolymer blends affects the development of crystallization, resulting in reduced crystallinity and diminished spherulite size. More importantly, the polar groups in the copolymer blends significantly increase the density of deep traps which suppress the space charge injection and enhance the DC breakdown strength. These findings suggest that this novel insulating material holds promising prospects in the field of DC cable insulation.