Sugar-template method to construct a boron nitride filler network to enhance the thermal conductivity of epoxy composites

In this work, a technique for constructing a three-dimensional (3D) skeleton of hexagonal boron nitride (h-BN) using sugar as the fulcrum and preparing composites by embedding in the epoxy (EP) in a vacuum environment is proposed. The study of thermal conductivity (TC) in polymer composites is conducted through a blend of techniques: laser flashing, theoretical modeling, and finite element simulation. The h-BN skeleton exhibits a honeycomb structure through the scanning electron microscopy findings. Further investigation using finite element simulation demonstrates that conductive networks are formed by the h-BN skeleton within the composites, leading to a notable enhancement in TC. Specifically, the composite for h-BN/EP reaches a TC of 2.25 W/m K when composed of 52 vol% h-BN. A dielectric loss of 0.008 for the composite with the same h-BN loading shows a considerable improvement. The compressive yield strength of the 3D h-BN/EP composites reached 312 MPa at 5 vol% h-BN loading.