Strong, Tough, and Thermally Conductive Nacre-Inspired Boron Nitride Nanosheet/epoxy Layered Nanocomposites

Thermally conductive polymer nanocomposites integrated with lightweight, excellent flexural strength, and high fracture toughness (KIc) would be of great use in many fields. However, achieving all of these properties simultaneously remains a great challenge. Inspired by natural nacre, here we demonstrate a lightweight, strong, tough, and thermally conductive boron nitride nanosheet/epoxy layered (BNNEL) nanocomposite. Because of the layered structure and enhancing the interfacial interactions through hydrogen bonding and Si–O–B covalent bonding, the resulting nacre-inspired BNNEL nanocomposites show high fracture toughness of ∼ 4.22 MPa·m1/2, which is 7 folds as high as pure epoxy. Moreover, the BNNEL nanocomposites demonstrate sufficient flexural strength (∼ 168.90 MPa, comparable to epoxy resin), while also being lightweight (∼ 1.23 g/cm3). Additionally, the BNNEL nanocomposites display a thermal conductivity (κ) of ∼ 0.47 W/(m·K) at low boron nitride nanosheet loading of 2.08 vol.