Novel functionalized BN nanosheets/epoxy composites with advanced thermal conductivity and mechanical properties.

The effective dissipation of heat is critical to the performance and longevity of high power electronics, so it is important to prepare highly thermally conductive polymer-based packaging materials for efficient thermal management. Due to the excellent thermal conductivity of BNNS, the hBN powder was dissolved in a mixed solution of isopropanol and deionized water for ultrasonic exfoliation to obtain hydroxylated BN nanosheets. Then, the prepared BNNS was functionalized with 3-aminopropyltriethoxysilane to enhance its dispersibility and interfacial compatibility in the epoxy resin, which plays an important role in the improvement of thermal conductivity of the composites. Finally, APTES-BNNS was uniformly dispersed in epoxy resin by solvent mixing, and the oriented APTES-BNNS/epoxy composites were prepared through spin-coating and hot-pressing method. It was found that APTES-BNNS/epoxy composites prepared herein exhibited significant anisotropic thermal conductivity. The results show that the thermal conductivity of APTES-BNNS/epoxy composites reached 5.86 W/mK at a filler content of 40 wt%, and has favourable thermal stability and mechanical properties. The APTES-BNNS/epoxy composite prepared in this paper has excellent thermal management capability and can be applied to the packaging of high-power electronic devices.