Improvement of mechanical properties and thermal conductivity of carbon fiber laminated composites through depositing graphene nanoplatelets on fibers

In this study, a graphene nanoplatelets (GnPs)/acetone solution containing a small amount of resin/hardener was prepared as the spraying solution for modifying dry fabrics which are well compatible with the vacuum-assisted resin transfer infusion (VARI) process, and the GnPs-reinforced fiber laminated composites with GnPs uniformly distributed in the interlaminar regions were successfully fabricated. The results showed that the GnPs are well immobilized on the surface of carbon fibers after spray coating, and the mechanical properties and thermal conductivity of the carbon fiber/epoxy composites were effectively improved. The incorporation of 0.3 wt% GnPs produced the largest flexural strength and interlaminar shear strength, and the reinforcing mechanisms as well as failure modes of the composites were proposed. It was also noticed that the through-plane thermal conductivity of the composites consistently increases with increasing GnPs content due to the formation of effective conductive pathways between the interplies. The study suggested that the developed up-scalable spraying technique is an effective approach to deposit GnPs on dry carbon fabrics which are compatible with the economical VARI process for producing GnPs/fiber/epoxy multiscale composites with enhanced properties.