Development of thermal conductive PMMA/BN electric insulating composite material produced by electrostatic adsorption method

The electrostatic adsorption method can be used to produce composite materials with an arbitrary structure, and their properties may be tuned by changing the size of the individual components, which in turn alters the composition of the material. To develop a thermally conductive and electrically insulating composite material with high thermal conductivity and an acceptable breakdown strength, polymethylmethacrylate (PMMA)/hexagonal boron nitride (h-BN) composite materials were produced by electrostatic adsorption method. The resulting composites possess flaky surfaces of h-BN which are oriented parallel to the electric field and the thermal conductivity measurement direction (the sample thickness direction). On increasing the PMMA particle size, the breakdown strength increases, although a corresponding decrease in thermal conductivity occurs. The variation in these properties is found to relate to the total h-BN content and/or the orientation angle of the flaky surface of h-BN relative to the thermal conductivity measurement direction.