Designing strong interfacial adhesion between carbon fiber and epoxy resin via dopamine towards excellent protection ability under high hydrostatic pressure and severe erosion corrosion condition

Abstract The complex marine environment in the splash zone and the deep-sea area is always raising stern challenges for the steel structures served in the offshore facilitates. Compared with other coating fillers, the carbon fiber (CF), with outstanding mechanical strength, is a suitable candidate filler for coating reinforcement. However, CF has a poor compatibility with organic resin, which could cause defects inside the coating, and result in coating failure further. Hence, we used dopamine to modify CF surface (CF-PDA) and introduced CF-PDA into the epoxy coating as reinforced additive to improve the erosion wear resistance and anti-corrosion ability of coating. The interfacial shear strength (IFSS) of CF-PDA/epoxy was increased by 32.20%, compared with CF/epoxy. After 120 h immersion under 30 MPa pressure, the |Z|0.01 Hz of the CF-PDA/EP (1.04 × 108 Ω cm2) was obviously higher than EP, and the interfaces of steel/coating and CF-PDA/resin were not failure evidently. Meantime, after the erosion wear test, compared with EP, the mass loss and the volume loss of CF-PDA/EP were decreased by 19.40% and 25.72%, respectively. Then, the failure process of coatings was discussed during erosion wear test, and we explained the relationship between the erosion wear resistance of coatings and interfacial strength of CF-PDA/epoxy resin.