The incorporation of a corrosion inhibitor (2-benzothiazolyllthiosuccinic acid) in polyoxyphenylene coatings prepared by in situ electropolymerization

Polyoxyphenylene coatings have been obtained on mild steel by in situ clectropolymerization of phenol/2-allylphenol mixtures in the presence of 2-benzothiazolylthiosuccinic acid (MBTS), a corrosion inhibitor of Fe. MBTS interferes only slightly with the electropolymerization process and is incorporated in the coating at concentrations slightly higher than its concentrations in the electrolytic solutions. Accelerated corrosion tests (a.c. impedance) have shown that a 1.5% MBTS content markedly enhances the corrosion resistance properties of coated samples exposed to 3% NaC1 solutions. MBTS was also tested as an inhibitor for bare mild steel exposed to NaCI solutions of variable concentration; it was found that the inhibitor acts mainly on the anodic process and that its effectiveness degrades as the NaCI concentration increases.