Highly thermally conductive polybenzoxazine composites based on boron nitride flakes deposited with copper particles

Abstract To solve the heat diffusion problem in electronic packaging, a novel kind of irregularly shaped hybrid filler, boron nitride@copper (BN@Cu), was successfully assembled via reduction of Cu2+. BN@Cu hybrid fillers composed of different mass ratios between BN and Cu have been prepared and characterized. A specific BN@Cu hybrid filler (mBN:mCu = 100:2), labeled as BN@2Cu, exhibited remarkable ability in enhancing the thermal conductivity of polybenzoxazine (PBz) composites fabricated through ball milling followed by hot pressing. With 25 wt% of BN@2Cu hybrid fillers, the thermal conductivity of PBz composites reaches 1.049 W m−1 K−1. Dielectric properties, electrical conductivity, and curing behavior of the composites were also investigated. In addition, Foygel's thermal conduction model was employed to demonstrate the mechanism of BN@2Cu hybrid filler in improving thermal conductivity.