Graphene-based hierarchical structure for significantly enhancing thermal conductivity of composites with high mechanical reinforcement

Abstract

Significant enhancement in out-of-plane thermal conductivity of carbon fiber/epoxy laminated composites without sacrificing mechanical strength is of great challenge for advanced composites. In this study, a novel graphene-based hierarchical structure was constructed by combining graphene foams (GrFs) with graphene nanoplatelets (GNPs) together and laminating with carbon fiber (CF) fabrics. The GrFs acted as thermally-conductive skeletons in bridging CF fabrics together to remarkably increase out-of-plane thermal conductivity of composites, while the GNPs were helpful to further increasing heat-transfer paths and effectively transferring stress between continuous CFs for high mechanical reinforcement. The hierarchical composites exhibited extremely high out-of-plane thermal conductivity of 2.64 W/m·K, increasing by 158.8 % than that of CF/Ep composites, and they also showed satisfactory tensile, flexural, and interlaminar shear strength. Such high performance is mainly due to the hierarchical structure, continuous heat-transfer paths, synergetic enhancement of GrFs with GNPs, and strong interfacial interactions between components for high-efficiency heat and stress transfer.