Facile Liquid-Exfoliation Process of Boron Nitride Nanosheets for Thermal Conductive Polyphthalamide Composite

In this study, we describe the fabrication of thermally conductive composites based on a polyphthalamide (PPA) matrix by the exfoliation of hexagonal BN nanosheets (BNNs) via the melt-mixing method. Boron nitride (BN) particles were hydroxyl groups surface-treated with sodium hydroxide (NaOH). Compared with existing BN peeling experiments, we successfully produced BNNs that are simpler, more economical, and have an excellent aspect ratio. For the same weight content of BN and BNNs, PPA/BN composites surface-treated with high aspect ratio BNNs have a high in-plane and through-plane thermal conductivity because of the intercalation of the hydroxyl group surface treatments between BN and PPA, which not only increases the wettability but also provides a good heat transfer path. Moreover, wide and thin BNNs are evenly dispersed inside the PPA/BN composite to provide excellent heat transfer paths in both in-plane and through-plane directions.