Design of Polymeric Corrosion Inhibitors Based on Ionic Coumarate Groups

Efficient, environmentally friendly organic corrosion inhibitors are being sought to alleviate the financial loss caused by corrosion degradation of mild steel materials. Here, we show the synthesis and characterization of monomeric ionic coumarate corrosion inhibitors and their integration into polymeric acrylic UV coatings. For this purpose, we investigated the effect of including the coumarate corrosion inhibitors into the acrylic UV coating by three different means. The corrosion inhibitors could be added as a standalone ionic liquid additive, or they can be ionically attached or covalently attached to the acrylic polymer network. To achieve this, two methacrylic monomers and one nonpolymerizable ionic coumarate compound were synthesized. The anticorrosion properties of the three coumarate compounds when added to a chloride aqueous solution were investigated by various techniques. Next, the three ionic coumarate compounds were integrated into an acrylic UV polymer composition. Here, the UV coating, which shows the best anticorrosion performance, was the one where the coumarate group is attached covalently or ionically to the polymer. The UV coating, which included the coumarate compound as a nonreactive additive, presented leaching problems from the coating, limiting its anticorrosion effect. The work herein shows that the development of polymeric corrosion inhibitors that combine the barrier properties of the polymer coating and the anticorrosive identity of the organic inhibitor is a powerful strategy to prevent corrosion.