Exfoliation of hexagonal boron nitride assisted with hierarchical ionic fragments by ball‐milling for achieving high thermally conductive polymer nanocomposite

Abstract

AbstractHexagonal boron nitride nanosheets (BNNSs) are considered as ideal candidates for preparing thermally and insulating composite because of its excellent thermal and electrical properties. Herein, we propose a facile and efficient ball‐milling way to exfoliate hexagonal boron nitride (h‐BN) with the assistance of coordination polymers (CPs). During the exfoliation process, the CPs occurs crystal to liquid/glass transition, forming diverse molecular fragments. The hierarchical ionic fragments can interact with and intercalate into the layered h‐BN, leading to a high efficiency in exfoliation and good dispersion. The exfoliated BNNSs reach a yield of up to 34% approximately. Furthermore, the BNNSs were incorporated to poly(vinyl alcohol) to prepare composite with thermal conductivity reaching up to 11.5 W m−1 K−1 at 30 wt% of BNNSs loading. The composite exhibits good performance on LED thermal management. This work demonstrates an efficient way to exfoliate BN, which can shed some light on other two dimensional materials exfoliation and application.