Preparation and Dielectric Properties of Polyethylene Composites Modified by Nano‐ TiO 2 Coated Zeolites With Different Pore Sizes

Abstract

ABSTRACT Low‐density polyethylene (LDPE) insulation in high‐voltage direct current (HVDC) cables is prone to space charge accumulation and electric field distortion. To address this, we propose a core–shell modification strategy using nano‐TiO 2 ‐coated porous zeolites (4A and NaY) synthesized via a sol–gel method to fabricate TiO 2 @zeolite/LDPE composites. Characterizations confirmed successful core–shell construction and enhanced nanofiller dispersion. Dielectric analyses reveal that the porous frameworks and core–shell interfaces synergistically introduce abundant deep traps. These traps efficiently capture charges under high fields, significantly reducing electrical conductivity, elevating the threshold electric field, and blocking long‐range carrier transport. Consequently, the composites exhibit substantially improved AC and DC breakdown strengths. Notably, the NaY zeolite, possessing a larger pore size, exhibits an optimal synergistic effect with the TiO 2 shell, yielding the most significant enhancement in comprehensive dielectric performance while maintaining low dielectric loss. This study elucidates the synergistic regulatory mechanism between porous frameworks and metal oxide coatings, offering a novel theoretical reference for designing high‐performance polymer nanodielectrics.