Synergetic enhancement of thermal conductivity and electrical insulating properties in the hexagonal boron nitride coated on silica (SiO2@BN)/BN/Epoxy composites

Abstract Thermally conductive insulating polymer composites are crucial for electronic packaging and motor potting due to their chemical resistance, easy processing, and low cost. Epoxy resin (EP) is widely used in power electronic device packaging materials for its excellent adhesive and electrical insulating properties. However, pure EP has low thermal conductivity. Enhancing both thermal and electrical properties is challenging because inorganic fillers like SiO 2 and BN often disperse poorly and have incompatible interfaces with the polymer matrix, leading to weak filler-matrix adhesion and reduced performance. Inorganic particles were surface-treated with silane coupling agents (KH550 and KH560) using a liquid-phase modification technique to address these issues. Subsequently, SiO 2 @BN/BN/EP composites were synthesized through blending. Experimental results showed that the modified Si 3 BN11 composite achieved a thermal conductivity of 0.78 W·m −1 ·K −1 at 25 °C, a 339.4% increase compared to pure EP. Additionally, this composite exhibited superior electrical insulation, with a breakdown strength of 87.7 kV/mm. These advancements improved thermal and electrical performance, enhancing the applicability of EP-based composites in electronic packaging.