Thermal conduction behavior of graphene and graphene-polymer composites

This chapter presents a comprehensive overview of the most recent advances on the factors that influence the thermal conductivity of graphene and graphene base polymer composites. Unlike the metals, where heat conduction is controlled by electrons, all-carbon derivatives such as diamond, graphene, and nanotubes owe their high thermal conductivity primarily to the phonons. The mechanically exfoliated graphene possesses the highest thermal conductivity of any graphene material produced to date. However, the perfect single layer graphene has yet to be realized commercially and for that, it is necessary to study the effect of several factors that influence the thermal conductivity of graphene when produced through other methods. We discussed the results of actual experiments and simulation studies that were carried out by several researchers in recent years for understanding the mechanisms which control the thermal conductivity of graphene and graphene-polymer composite materials. Particularly, we discussed the effects of processing conditions, measurement methods, graphene sheet size, grain size, edges, defects, sheet orientation, covalent or non-covalent functionalization and novel architectures to tune the thermal conductivity of graphene. The chapter aims to clarify the differences in thermal conductivity results among several published reports, where any of the extrinsic factors can influence or alter the thermal conductivity of graphene and graphene-based polymer composites.