Synergistic Modulation of Thermal Conductivity and Electrical Insulation in Polypropylene Composites via ( FeCoCrMnZn ) ₃ O Xingchu He, Shuai Zhang, Weiqiang Song, Shunli An, Hongsen Wang, Shuaitao Wang, Tengfei Yu

ABSTRACT

The urgent demand for advanced electrical insulation materials with simultaneous high thermal conductivity and excellent electrical insulation has driven the development of high‐performance polymer composites. In this work, polypropylene (PP)‐based hybrid composites were fabricated via melt blending, incorporating spinel‐type (FeCoCrMnZn) ₃ O ₄ high‐entropy oxide (HEO) and two‐dimensional α‐zirconium phosphate (ZrP) as hybrid fillers. The synergistic modulation effects of HEO and ZrP on the crystallization behavior, mechanical robustness, thermal conductivity, and electrical insulation properties of the composites were systematically investigated. Results demonstrated that low loading of HEO (2 phr) effectively reinforced and toughened PP, with tensile strength and impact strength increased by 4% and 86%, respectively, while the thermal conductivity was enhanced by 90.5% at 20 phr HEO loading due to the formation of thermally conductive networks. The introduction of ZrP exerted a heterogeneous nucleation effect, increasing the crystallization temperature by up to 2.8°C, and constructing a physical barrier via the “maze effect” to significantly improve volume resistivity, which reached 8.05 × 10 ¹⁶  Ω·cm for PP‐2HEO/6ZrP. Notably, the PP‐5HEO/2ZrP composite exhibited the optimal comprehensive performance, achieving a high impact strength of 26.8 kJ/m ² , favorable thermal conductivity, and exceptional electrical insulation stability. The synergistic mechanism was attributed to the complementary roles of HEO (thermal conduction and rigid support) and ZrP (nucleation, barrier, and toughening), which optimized interfacial compatibility, regulated crystal structure, and activated multiple energy dissipation pathways. This work provides a feasible strategy for designing high‐performance PP composites with integrated thermal management and electrical insulation capabilities, showing great potential for applications in 5G communication, new energy vehicles, and high‐voltage cable insulation.