Efficiency of Anti-Corrosion Protective Coatings Based on Graphene Oxides Functionalised with Green Inhibitors

Abstract

Mild steel (MS) is commonly used for infrastructure and machinery due to its various engineering properties and benefits, but they are highly prone to corrosion. For decades, organic polymeric coatings are widely applied to protect metallic systems against corrosion. Besides the physical barrier, the organic coatings have been manipulated by adding anti-corrosion pigments or corrosion inhibitors, such as red-lead or chromate to enhance protection. However, these conventional anticorrosive pigments have been substituted because of their toxicity and environmental problems. Recent studies have been consequently conducted to develop environmentally safe and green alternatives obtained from natural products.In the framework of this study, a novel green hybrid pigment nano-pigment based on graphene oxide (GO) and an organic natural inhibitor was prepared and included in a Polyvinyl Butyral (PVB) coating. The protective properties of PVB coatings without and with the addition of GO and f-GO on steel in 3.5wt% NaCl solution were studied by electrochemical methods.The new pigment functionalised GO (f-GO) is not only able to be an outstanding barrier, but it can also store a considerable amount of corrosion inhibitors and release them, when necessary, on the protective coating system. GO was functionalised with the green inhibitor in aqueous phase and the compound obtained was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analysis (TGA), ultraviolet-visible spectroscopy (UV-Vis) and atomic force microscopy (AFM).FT-IR and UV-Vis spectroscopy results indicated that the organic compound effectively reduced GO into f-GO and PVB/f-GO composite coatings showed 100 times higher anticorrosion resistance than PVB/GO and neat PVB. Figure 1