Aromatic amine‐epoxidized sunflower free‐fatty‐acid adducts as corrosion inhibitors in epoxy‐curable varnishes

AbstractWith strict regulation of environmental pollution, sunflower fatty acids were used to prepare high‐molecular‐weight aromatic amine adducts by reaction of their epoxidized form [epoxidized sunflower free fatty acid (ESFA)] with five aromatic amines [o‐toluidine (o‐T), m‐toluidine (m‐T), p‐toluidine (p‐T), p‐anizidine (p‐A), and p‐chloroaniline (p‐ClA)] under severe conditions of an inert atmosphere and high temperature. The produced adducts were characterized physically, chemically, and by IR spectroscopy. The acid values and oxirane contents of the prepared adducts were determined to confirm the participation of carboxylic groups and epoxy groups, respectively, in the reaction of ESFA with aromatic amines. Also, to avoid volatile organic compounds, the prepared adducts of ESFA (o‐T–ESFA, m‐T–ESFA, p‐T–ESFA, p‐A–ESFA, and p‐ClA–ESFA) were evaluated as corrosion inhibitors of mild steel in electron‐beam‐curable epoxy acrylate oligomer formulations. Physical and mechanical measurements were carried out, in addition to corrosion‐resistance tests and weight loss measurements of the coated steel panels. The optimum concentration of each adduct was determined for the prepared formulations. The corrosion‐inhibition efficiency of the adducts in varnish formulations were determined. It was found that varnish formulations containing the prepared aromatic amine adducts could protect steel from corrosion. The corrosion‐inhibition efficiencies of the prepared aromatic amines in epoxy acrylate oligomer varnishes were arranged as follows: p‐A–ESFA > p‐T–ESFA > m‐T–ESFA > o‐T–ESFA > p‐ClA–ESFA. Superior corrosion‐inhibition efficiency was obtained in the varnish formula containing 0.6% p‐A–ESFA adduct. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012