LAUSR

Phthalonitrile resin/exfoliated hexagonal boron nitride (h-BN) composites with high thermal conductivity were fabricated using a novel approach. The route included two steps, micro-h-BN was coated and dispersed by phthalonitrile monomers via the function of heterogeneous nucleation, and then micro-h-BN was exfoliated by heat release during the phthalonitrile curing process. The composites achieved a high thermal conductivity of 0.736W (m·K)−1 containing 20 wt% micro-h-BN, which is 3.17 times higher than that of pure phthalonitrile resin at 0.232W (m·K)−1. Compared to traditional routes, the novel preparation approach requires less BN fillers when improving the same thermal conductivity. Importantly, other thermosetting polymers can also encapsulate BN through this strategy, which paves a new way for preparing thermally conductive thermosetting polymer–matrix composites.