Fabrication and Thermal Conductivity Optimization of Epoxy Composites With Multidimensional Hybrid Fillers

ABSTRACT Utilizing the self‐polymerization property of dopamine, boron nitride (BN) was coated with polydopamine (PDA) to prepare BN@PDA. A biphenyl type epoxy resin (MBE) and 4,4′‐diaminodiphenyl sulfone curing agent were selected to fabricate BN@PDA/MBE composites. The composite structure was characterized via Fourier‐transform infrared spectroscopy, x‐ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy, while its flexural strength, dielectric properties, and thermal conductivity were systematically investigated. Results demonstrate that PDA significantly improves the compatibility between BN and the resin matrix. The composite with 5 wt% BN@PDA exhibited enhanced mechanical performance. Thermal conductivity analysis revealed that the 20 wt% BN@PDA/MBE composite achieved optimal thermal conductivity [0.441 W/(m·K)]. Furthermore, copper nanowires (CuNWs) were coated with PDA, and the synergistic integration of BN@PDA and CuNWs@PDA fillers was achieved via PDA's adhesive properties. The BN@PDA‐CuNWs/MBE composite containing 3 wt% CuNWs@PDA demonstrated superior thermal conductivity [0.461 W/(m·K)], highlighting the effectiveness of hybrid filler design in enhancing heat transfer performance.