Waterborne methylamine adduct as corrosion inhibitor for surface coatings

Soybean oil was epoxidized using peracetic acid prepared in situ from acetic acid and hydrogen peroxide with Dowex 50 W-8X as a catalyst. The epoxidized soybean oil was allowed to react with methylamine. The resulting adduct was identified and emulsified. The emulsified methylamine adduct was added at different concentrations to an emulsion (styrene/acrylic)-based paint (blank). The effect of the methylamine adduct concentration on the physical, chemical, and mechanical properties of the paint was studied. Various tests such as metal substrate weight loss, corrosion, blister, and scratch resistance were performed to evaluate the efficiency of the prepared adduct. It was found that there is an optimum concentration at which the methylamine adduct is very effective as a corrosion inhibitor. This concentration is about 0.5% by weight. In comparison with chromate anticorrosive pigment, it was found that the methylamine adduct is superior with more economical and environmental advantages. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 286–296, 2001