Morphological and mechanical relaxation characteristics of nano-SiC/crosslinked polyethylene insulation composites

Crosslinked polyethylene (XLPE) possesses excellent dielectric properties, including low electrical conductivity, low loss, and high breakdown strength. Because it is also environmentally friendly and chemically resistant, XLPE is widely used as insulation for high-voltage direct current (HVDC) cables. Modification of XLPE is a research hotspot in electrical engineering, and nanocompositing has proven particularly effective for this purpose. The dielectric properties of XLPE nanocomposites are closely related to the morphology, structure, surface chemistry, size, amount, and dispersivity of the incorporated nanoparticles. Silicon carbide (SiC) is a representative nanoparticle with a large specific surface area and high surface activity. It is widely used in polymer applications to enhance mechanical properties. The addition of SiC introduces physical crosslinking points, significantly improving the mechanical performance of the composites. Therefore, incorporating nano-SiC into XLPE can strengthen the interactive forces between matrix macromolecules, ultimately affecting the morphology, relaxation behavior, and macroscopic properties of the polymer. In this study, nano-SiC particles were employed as fillers to prepare nano-SiC/XLPE composites, and their morphology and relaxation properties were comprehensively investigated.