Mussel-inspired synergistic anticorrosive coatings for steel substrate prepared basing on fully bio-based epoxy resin and biomass modified graphene nanoparticles

Abstract

Traditional epoxy anticorrosive coatings face challenges such as reliance on non-renewable petroleum resources, environmental pollution, brittleness and poor long-term anticorrosion performance. In this work, the bio-based coatings are fabricated to address the above issues by using epoxidized soybean oil (ESO) as the resin matrix, tannic acid (TA) as curing agent and modified graphene (TH-rGO) nanoparticles as functional fillers. Inspired by mussels, the phenolic hydroxyl groups of TA are fully used, so that the coating has in-situ adhesion to the steel substrate. The TH-rGO nanoparticles, formed by grafting L-histidine onto GO and reducing them with TA, exhibit favourable dispersion stability in epoxy coating suspension. And the prepared coating films exhibit favourable tensile ductility with the strain of higher than 14%, thermostability with the initial degradation temperature above 300 ℃, as well as impervious performance and antimicrobial activity. Furthermore, the results of electrochemical impedance spectroscopy test demonstrate that after 8 weeks of immersion in simulated seawater, the low-frequency impedance modulus at 0.01 Hz of the nanocomposite coating with optimal nanoparticles content reaches 4.42×109 Ω cm2, resulting in favourable durability of anticorrosion performance. This study presents a facile fabrication approach of bio-based epoxy coatings with durable anticorrosion performance, demonstrating potential for industrial applications.