Construction of <scp>3D</scp> modified <scp>hexagonal boron nitride</scp> thermal conductivity network by ice template method and research of high heat‐conducting coefficient of epoxy resin matrix composite material

Abstract This paper investigates the high thermal conductive properties of modified hexagonal boron nitride (h‐BN)/epoxy (EP) composites. Octadecyl trimethyl ammonium bromide as a cationic surfactant modified h‐BN and sodium carboxymethylcellulose to build 3D heat transfer framework by the ice template method and preparation of epoxy composites. The h‐BN was modified by inter‐ionic charge electrostatic attraction to improve the h‐BN dispersibility; characterization by scanning electron microscope, transmission electron microscope, zeta potential, x‐ray diffraction and Fourier transform infrared spectroscopy proved the success of h‐BN surficial modifyment. 3 wt% sodium carboxymethylcellulose was used to construct the optimal 3D modified h‐BN network, and the w‐BN/EP composites had a very high heat conduction; when the composite material acquired by the ice template method have high heat transfer coefficient, 1.57 W/(m K) for 25 wt% 3D modified h‐BN/EP heat transfer coefficient and 0.76 W/(m K) for modified h‐BN/EP at the same ratio, which is a 107% enhancement in heat transfer efficiency, and 0.12 W/(m K) for EP, which is a 1208% enhancement in thermal conductivity. The results of thermogravimetric analysis (thermogravimetric analysis and differential thermogravimetric analysis), differential scanning calorimetry, and infrared thermography indicate that the thermostability and rejection of heat of composite material was significantly improved. The variation of dielectric constant was stabilized to ensure lower dielectric loss. Overall, this study can better adapt to high‐frequency signal transmission. Highlights Use octadecyl trimethyl ammonium bromide to modify the interface of hexagonal boron nitride (h‐BN) enhances the dispersibility and reduces the inter‐facial heat resistance with epoxy resin through inter‐ionic electrostatic attraction. The optimal content of sodium carboxymethyl cellulose was selected to construct a 3D mesh framework with the modified h‐BN to ensure the formation of a continuous and homogeneous network at the maximum porosity. The 3D modified h‐BN network was prepared by the ice template method to reinforce the heat conductivity of the composite materials.