Fabrication of polyaniline/waste sugarcane bagasse composite fillers for excellent anti-corrosion protective coatings

Abstract

Herein, biomass-based anti-corrosion composite fillers for water-based epoxy resin coatings, epoxy resin powder coatings, and efficient anticorrosive coatings were successfully prepared. Polyaniline/sugarcane bagasse composites (PANI–SCB) were prepared by in situ polymerization after the sugarcane bagasse was ground into a powder with a planetary ball mill. SEM results showed that a large number of loose polyaniline particles were formed on the surface of bagasse. Electrochemical testing showed that the water-based epoxy resin coating with 1% PANI–SCB had a low corrosion current density (5.466 × 10⁻⁷ A cm⁻²) and the highest low-frequency impedance modulus (34 260 Ω cm⁻²). The high protection efficiency (99.57%) and slow decline in impedance with a long soaking time indicated satisfactory anti-corrosion performance. On this basis, the prepared powder coating with 3% PANI–SCB presented a low corrosion current and high protection efficiency (99.39%). In addition, the powder coating had considerable adhesion fastness, flexibility, and commercially viable chemical resistance. XRD analysis found that the presence of Fe₂O₃ and Fe₃O₄ in the corrosion products can effectively induce the formation of a dense passivation film, thereby improving the corrosion resistance. The economic and environmental composite coating is expected to function in the anti-corrosion maintenance of hydropower station facilities.