Enhance the thermal conductivity and maintain insulation property of epoxy via constructing a three-dimensional network by doping hexagonal boron nitride and carbon nanofiber

It is of great significance for polymers used in electrical systems to maintain insulation property while improving the thermal conductivity of them. In order to achieve this goal, this paper used hexagonal boron nitride (h-BN) and a small amount of carbon nanofibers (CNF) as filling phase, prepared thermally conductive insulating dielectric materials based on epoxy. An effective heat transport network is formed in the material by the synergistic effect of the two-dimensional structure of h-BN and the one-dimensional structure of CNF, thereby improving the thermal conductivity of the composite materials. The thermal conductivity of the composite with the filling amount of 20 phr h-BN & 0.001 phr CNF reached 0.505 W/(m K), which is 188.6% higher than that of pure epoxy. At the same time, the composites also exhibited higher insulating strength under DC conditions and lower tangent of the dielectric loss angle in a wide frequency range. This simple mixing strategy provides a new way for the preparation and research of thermally conductive and insulating polymer materials.