Advanced Thermal Interface Materials Using Natural Graphite

Expanded flexible graphite sheet materials have become attractive as Thermal Interface Materials (TIM’s). Flexible graphite sheet materials were originally developed as gaskets for fluid sealing applications. Properties that make flexible graphite sheets of interest as TIM’s include their relatively high thermal conductivities and their ability to conform well to surfaces. Specific grades of flexible graphite have been developed for TIM applications. Because flexible graphite sheets are porous, with open interconnected pores, it is possible to impregnate these sheets with various materials to improve properties. In particular, various polymers, such as mineral oils, synthetic oils, etc can be added to flexible graphite to improve its performance in thermal interface applications. This paper will review the thermal properties of TIM’s made by adding two different polymeric materials to a grade of flexible graphite specifically developed as a thermal interface material.