In this study, to enhance the thermal stability and electrical insulation of the composite specimens in addition to the improved mechanical property, the epoxy composite were reinforced with carbon nanotubes and silica particles. FE-SEM, tensile strength, dynamic mechanical analysis, coefficient of thermal expansion, thermal diffusivity and electrical resistivity were measured for the specimens with varied contents of the two fillers, and the mechanical, thermal and electrical properties were discussed. Also, the experimental results related with the mechanical property and thermal stability of the specimens were compared with those from several micromechanics models. Hybrid composites specimens with 0.6 wt% of carbon nanotubes and 50 wt% of silica showed the higher mechanical properties with tensile strength and Young’s modulus increased by up to 11% and 35%, respectively, with respect to those of baseline specimen. Base on the results storage modulus at the glass transition region of the fabricated specimens were increased with the contents of the two fillers.
Furthermore, as the silica contents were increased the thermal expansion was reduced down to 36%, and the thermal stability was improved with the decreased thermal deformation. But the thermal deformation of the specimens with the contents of carbon nanotubes were increased by the enlarged heat transfer to the specimens. Moreover, due to the higher thermal conductivity of the two fillers the thermal diffusivity of hybrid composites specimens were higher than that of baseline specimen. Electrical conductivity of the composite specimens with carbon nanotubes were improved. Also, thermal stability and electrical insulation of the hybrid composites specimens with the two fillers was improved in addition to the enhanced mechanical property.