Abstract
Epoxy resins with controlled high-order structures show higher thermal conductivity than conventional ones, because the crystal-like domains consisting of self-arranged 'mesogen' groups of epoxy monomers promote smooth phonon transportation. Thermal conductivity of these epoxy resins is 1.0 W/mK at most, and this value is not enough to apply these neat resins to electric devices which require high radiation efficiency. In this paper, we investigated the composites consisting of these resins and ceramic fillers, in order to obtain the epoxy resin composites which have both isotropic high thermal conductivities and electrical insulation. Though these epoxy monomers are difficult to handle because of their crystallinity and poor solubility in solvents, we confirmed that the conventional processes for thermosetting resin forming, such as “varnish coating” and “transfer molding”, are applicable to these composites by optimizing the molecular architectures of hardeners, the composition of solvents, etc. As a result, excellent thermal conductivity as high as 10 W/mK was attained for the composites using the polycyclic mesogen type epoxy monomers.
