Ultra high thermal conductivity polymer composites

Epoxy composites based on vapor grown carbon fiber (VGCF) were fabricated and analyzed for room temperature thermophysical properties. An unprecedented high thermal conductivity of 695 W/m K for polymer matrix composites was obtained. The densities of all the composites are lower than 1.5 g/cc. In addition the high value of coefficient of thermal expansion (CTE) of the polymer material was largely reduced by the incorporation of VGCF. Also, unlike metal matrix composite (MMC), the epoxy composite has an electrically insulating surface. Based on the composite thermal conductivities, the room temperature thermal conductivity of VGCF, heat-treated at 2600 °C, was estimated to be 1260 W/m K. Furthermore, the longitudinal CTE of the heat-treated VGCF was determined, for the first time, to be -1.5 ppm/K.