Silk fibroin-Ti3C2TX hybrid nanofiller enhance corrosion protection for waterborne epoxy coatings under deep sea environment

Abstract

The complex and harsh deep sea environment is the main reason for the failure of the protective coating of marine equipment. However, excellent protective coating is the key to prolong the service life of the equipment under deep sea environment. Ti3C2TX, with high aspect ratio, abundant surface functional groups and excellent mechanical properties, is the suitable candidate nanofiller for coating reinforcement. Herein, we synthesized a novel silk fibroin-Ti3C2TX (SF-Ti3C2TX) hybrid nanofiller as reinforced-additives for improving the anti-corrosion ability of waterborne epoxy coating. Due to the rough surface of SF-Ti3C2TX nanosheets, they have excellent compatibility with the resin matrix and could fill the inherent defects of the coating. The anticorrosion behaviors of as-prepared composite coatings under both of atmospheric pressure and simulated deep sea environment were investigated in detail. Particularly, the composite coating with 0.5 wt% SF-Ti3C2TX sheets showed outstanding corrosion protection (impedance value remained 1.31 × 108 Ω⋅cm2, four orders of magnitude higher than pure EP) after 240 h immersion under 20 MPa hydrostatic pressure. In addition, the interface of coating/steel was not damaged and the coating remained the favorable adhesion strength (3.16 MPa, but that of pure EP only 0.88 MPa) even in the harsh high hydrostatic pressure. Based on the experiment data, we discussed and analyzed the failure process of coatings and explained the corrosion protection mechanism of SF-Ti3C2TX hybrid under simulated deep sea environment.