Improvement of Thermal Conductivities for Epoxy Composites via Incorporating Poly(vinyl benzal)-Coated h‑BN Fillers and Solvent-Assisted Dispersion

A solvent-assisted diffusion method is developed here to prepare thermally conductive epoxy composites (EP) after hexagonal boron nitride (h-BN) was modified via poly (vinyl benzal) (PVB) noncovalent bond coating. The h-BN@PVB with different PVB coating contents was prepared and verified by FT-IR, SEM, and TGA. Then, EPs loaded with 20 wt % filler were prepared by using these different PVB-coated particles to find the optimum value for PVB content. Finally, when introduced dimethyl sulfoxide solvent to the dissolve PVB shell after the dispersion of h-BN@PVB into epoxy resin, the thermal conductivities were similar to that of h-BN/EP at low filler levels, but larger at high filler loading because of the formation of flower-like thermal conduction paths. The thermal conductivity can reach 0.89 W m–1·K–1 at 40 wt % h-BN@PVB loading by using the solvent-assisted diffusion method, which is 4 times higher than that of native epoxy resin.