Preparation and properties of water-based composite anticorrosive coatings based on the environment in the Northeast China

To improve the dispersibility and corrosion protection against metal corrosion of doped graphene oxide (GO) in water-based acrylic resin (AP), GO was modified with hexamethylene diisocyanate, p-phenylenediamine, polyethylene pyrrolidone and 3-aminopropyltriethoxysilane to prepare reinforced dispersion graphene oxide (RDGO), which then combined with AP through wet transfer method to synthesize water-based anti-corrosion coating (RDGO/AP). The RDGO/AP coating obtained was characterized by FTIR, Raman, XRD, SEM and TGA, and evaluated for its anti-corrosion ability by electrochemical and corrosion experiments. The results showed that RDGO exhibited a two-dimensional crystal structure, with the interlayer spacing increased from 0.0761 nm of GO to 0.1045 nm, thus preventing the aggregation phenomenon of GO. The RDGO exhibited a mass loss starting temperature of 254 ℃, indicating good thermal stability. Compared with AP coating, the RDGO/AP coating showed an increase in water contact angle (98.00°) by 3.99°, the hardness (4H) by 2H, and the adhesion (level 1) by 2 levels. After soaked in a 3.5% (mass fraction) NaCl solution for 14 d, compared with the AP coating, the RDGO/AP coating had an increase in corrosion voltage by 0.479 V and decrease in the corrosion current density by 1.172×10–5 A/cm2, with a protection efficiency up to 99.9%. The good corrosion resistance of RDGO/AP could be attributed to the fact that the carbonyl groups on the surface of RDGO were prone to grafting with the hydroxyl group in AP, improving the dispersibility of RDGO in the acrylic resin, strengthening the interfacial adhesion, increasing the toughness and shear strength of the coating, and elevating the adhesion between RDGO and film-forming substrate, thereby enhancing the anti-corrosion effect of the coating. © 2024 Fine Chemicals. All rights reserved.