Influence of PMMA and h-BN particles sizes on electrical and thermal properties of PMMA/h-BN composite materials produced by electrostatic adsorption method

The electrostatic adsorption method can fabricate composite materials with an arbitrary structure. Changing a parameter such as the size of an individual component, which alters the composition, can adjust the composite material's characteristics. To develop a thermally conductive and electrically insulating composite material with a high thermal conductivity and an acceptable breakdown strength, a polymethyl methacrylate (PMMA)/hexagonal boron nitride (h-BN) composite material was produced by changing the h-BN filler size or the PMMA particle size using the electrostatic adsorption method. Regardless of the h-BN size, the DC breakdown strength and the thermal conductivity of the composite increased and decreased, respectively, as the PMMA size increased. For composites with the same sized PMMA particles, the breakdown strength of the composite with a larger h-BN particle size was smaller than that of the composite with a smaller h-BN particle size. The thermal conductivity between these composites showed an inverse trend to the DC breakdown strength. These characteristics are attributed to the length of the h-BN, the filler orientation, and the change in the distance between fillers.