Enhanced seawater corrosion resistance of glass fiber/epoxy composites by introducing a carbon nanotube-reinforced interfacial protective layer

To address the severe durability degradation of glass fiber-reinforced epoxy composites from seawater-induced fiber-matrix interfacial corrosion during long-term marine service, this study aims to enhance the seawater corrosion resistance of composites by constructing a multi-walled carbon nanotube (MWCNT)-reinforced interfacial protective layer. A novel interfacial reinforcement strategy was proposed, utilizing amine-functionalized MWCNTs to in-situ build a strongly bonded protective layer, effectively retarding the penetration of moisture and corrosive media. Glass fiber fabrics were modified with amine-functionalized MWCNTs, and composites were fabricated via vacuum-assisted resin infusion molding, followed by a 12-month simulated seawater immersion test. Results show that the functionalized MWCNTs significantly enhance fiber-matrix interfacial bonding via synergistic mechanical interlocking and proposed chemical interaction. The water absorption of composites increased progressively over 12 months, approaching equilibrium after approximately 10 months. The modified composite achieved up to 18.3% lower equilibrium water uptake versus the unmodified sample. After 12 months of artificial seawater exposure, the modified composites exhibit only a 5.6% reduction in interlaminar shear strength (from 83.2 MPa to 78.5 MPa), demonstrating superior performance retention relative to the unmodified composites (9.2% reduction).This work provides an efficient interfacial solution for marine composite durability and insights into the design of corrosion-resistant fiber-reinforced polymer composites.