Anisotropic thermal conductivity and flame retardancy of nanocomposite based on mesogenic epoxy and reduced graphene oxide bulk

Anisotropic thermal conductive polymer composite provides a bright prospect for thermal management in modern electronics device. Via infiltration, biphenyls mesogenic epoxy nanocomposite (AEO) is prepared based on mesogenic epoxy and reduced graphene oxide (rGO) bulk. Unlike common polymer composites, AEO shows an interesting anisotropic thermal conductivity phenomenon. The rGO sheet is prepared from reduction of graphene oxide (GO) via grafting phosphorus-containing compound, and then rGO bulk can be obtained by vacuum-assisted self-assembly method. In rGO bulk, basal plane of most rGO nanosheet is nearly parallel and it displays aligned laminated structure in in-plane direction. Between rGO nanosheets, an intercalated morphology and cramped spaces can be observed. As a result, in AEO, rGO- rGO linkages heat transfer channel in in-plane direction is formed and epoxy nanocomposite exhibits anisotropic thermal conductivity. In-plane and through-plane thermal conductivity of AEO is 1.3209 W m−1 K−1 and 0.1725 W m−1 K−1, respectively. Moreover, AEO exhibits excellent flame retardancy and mechanical strength.