Polyaniline‐grafted polyurethane coatings for corrosion protection of mild steel surfaces

ABSTRACT We report the superior corrosion‐resistant properties of conducting polyurethane networks of polyaniline (PANI), poly‐m‐aminophenol (PmAP), and poly‐o‐anisidine (PoA) coated on mild steel panels. These networks were prepared by blending conducting polyanilines with isocyanate‐containing prepolyurethanes. Free‐standing polyurethane films were obtained after a moisture cure for several days to ensure complete reaction of the excess isocyanate. The films were electrochemically active with conductivity in the range of 10−2 to 10−3 S/cm. The solution blends and formed films were characterized by infrared, ultraviolet, thermogravimetric analysis, and differential scanning calorimetry. Electrochemical corrosion studies of the coated films on mild steel panels showed excellent corrosion protection in the following order: PU‐PANI > PU‐PmAP > PU‐PoA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45806.