Comparative studies of anticorrosion performance of novel inhibitors based on oleic acid and sulfur/nitrogen containing compounds in UV-curable coatings

A natural resource-based oleic acid was epoxidised to produce epoxidised oleic acid (EOA). The epoxidation reaction was confirmed by different analyses. Then, EOA was reacted with nitrogen- and sulphur-containing compounds such as glycine (GLY) and thioglycolic acid (TGA) to prepare EOA-GLY and EOA-TGA compounds, respectively. The EOA, EOA-GLY, and EOA-TGA compounds were evaluated as corrosion inhibitors (CIs) for mild steel in different coating formulations. Corrosion resistance tests and weight loss measurements of the coated steel panels were carried out, in addition to the physico-chemical and mechanical measurements. It was found that the coating formulations containing the prepared EOA-TGA inhibitor with a concentration (0.04 g/100 g coating) imparted higher protection for steel surface against corrosion and also competed efficiency known commercial CI at the same concentration. Also, the efficiency of the commercial and prepared inhibitors was increased in the following order: EOA-TGA > EOA-GLY > commercial inhibitor > EOA.