Synergistic Enhancement of Mechanical and Thermal Properties in Polydopamine‐Modified Carbon Fiber/Graphene Oxide‐Epoxy Composites

Abstract

Carbon fiber‐reinforced polymer (CFRP) composites, which exhibit excellent mechanical performance and low density, suffer from low surface activity across various applications. Dopamine self‐polymerized on the carbon fiber surface via π‐π interaction to form a nano‐thin surface‐adherent polydopamine (PDA) layer to improve the bonding between the fiber and the epoxy resin. Graphene oxide (GO) was also added to the epoxy matrix to increase the mechanical strength of the composites. The objective of this study is to investigate the thermal and mechanical properties of PDA modified CFRP with embedded various GO loadings (0.25–0.75 wt.%). The composite laminates were fabricated through the vacuum‐assisted resin transfer molding (VARTM) process. The PDA modified carbon fiber was characterized using FT‐IR, XRD, and Raman Spectroscopy. As a result, both the tensile and flexural properties were effectively improved in the PDA‐modified carbon fiber reinforced epoxy (DCFRP) composite and the GO‐embedded DCFRP/GO/epoxy composites. The tensile strength, flexural strength, and glass transition temperature ( T g ) increased by 42.77%, 135%, and 11.6% at a GO loading of 0.50 wt.% compared to the bare CFRP composite. Overall, PDA modification of carbon fibers significantly enhanced both the thermal stability and mechanical performance of the composites, establishing this approach as a promising route for advanced structural applications.