Carbon-based Composites With High Thermal And Mechanical Properties By Controlling Their Microstructures

The rapid development of delicate electronic equipments,high-power engine systems and aircrafts has put forward the need of thermal management materials with low density and high thermal conductivity(?).At the microscale,individual carbon materials,such as graphene,carbon nanotube(CNT),and carbon fiber(CF)exhibit high?.Their high?arises from the strong covalent sp~2 bonds of carbon atoms that favor phonon transport through the lattice plane.However,these individual carbon materials cannot be used directly for heat sink devices.And one way is to assemble these individual carbon materials into carbon composites with high?.Different from individual carbon materials,carbon composites have assembled structures,including the interface,orientation,and pores.Expanded graphite,graphite sheet,and graphene with flexibility and high quality have been prepared from the oxidation and intercalation of nature graphite.Various carbon composites have been prepared by mixing these two-dimensional materials with themselves,CF,and CNT followed by hot pressing.The effects of material structures including interfaces,orientation,and pores on?of these composites are discussed.Also,the strategies to control the material structures and?of these composites are summarized,mainly including the preparation parameters of composites and the intrinsic structures of individual carbon materials.Meanwhile,the relationships between these control strategies and the thermal properties of carbon composites are discussed.The research results show that the?of carbon composites greatly depends on the bulk density and interface structures,and the?of carbon composites in three directions can be adjusted by controlling the micro orientation.To attain a high?of carbon composites,efforts have been made to adjust and control the structures.Carbon composite prepared from graphite sheet and vertical aligned CNT have showed a maximum cross-plane thermal conductivity of 34.9 W/mK,which is 149.2%higher than the composite without CNT.