Recyclable Dielectric Polymer Nanocomposites with Voltage Stabilizer Interface: Toward New Generation of High Voltage Direct Current Cable Insulation

Long-distance and large-capacity transmission systems have been strongly demanded in modern society, which requires the development of high voltage direct current (HVDC) cables. However, the currently used cross-linked polyethylene (XLPE) insulated cables not only cannot fulfill the environmental sustainability but also cannot withstand HVDC electrical stress. In this study, recyclable cable insulation which can withstand HVDC electrical stress was successfully prepared by incorporating newly synthesized voltage stabilizer functionalized silica nanoparticles into a thermoplastic isotactic polypropylene. The introduction of voltage stabilizer functionalized nanoparticles resulted in significantly enhanced breakdown strength, suppressed space charge injection, and greatly improved thermal stability. For example, the breakdown strength was increased by about 46% by adding 4 wt % voltage stabilizer functionalized silica. Surface potential decay, crystallinity, and supramolecular structure of the polypropylene nanocomposites were measured, and the improved electrical properties were mainly attributed to the shallow traps introduced by the voltage stabilizer functionalized silica. This investigation paved a new way for developing environmentally-friendly HVDC cable insulation.