Waterborne polyaniline-graft-alkyd for anticorrosion coating and comparison study with physical blend.

Graphical abstract The WAR-PANI was synthesized by graft PANI onto alkyd resin and its anti-corrosion properties were studied. The results demonstrated that PANI was successfully grafted onto the alkyd resin and WAR-PANI can offer higher corrosion protection than the WAR and WAR/PANI. Highlights • Anti-corrosion coating WAR-PANI was developed by graft PANI onto alkyd resin. • Comparison study was made between WAR-PANI and physical blend. • WAR-PANI displayed higher corrosion resistance than WAR and WAR/PANI. • WAR-PANI coating also presented long-term anti-corrosion properties. Abstract Waterborne polyaniline grafted alkyd resin (WAR-PANI) anti-corrosion coatings were prepared via the chemical reaction between glycidyl methacrylate (GMA) modified WAR and polyaniline (PANI). The physical blend of PANI and WAR (WAR/PANI) were also prepared for comparison. The obtained WAR-PANI was characterized by fourier transform infrared spectroscopy and transmission electron microscopy. The results show that PANI was successfully grafted onto the chain of WAR. Polarization tests displayed that the corrosion potential of PANI grafted WAR coating became more positive compared with WAR/PANI physical blend, and the cathodic corrosion was effectively inhibited. When the dosage of GMA was 2.67%, the anticorrosion performance of WAR-PANI composite reached the optimum, the corrosion potential shifted from −690 mV to −530 mV, and the corrosion current density decreased from 6.92 × 10−5 to 9.66 × 10−11 A cm2. Electrochemical tests further proved that the impedance modulus and coating resistance of WAR-PANI increased by four orders in comparison with WAR, which were also three orders of magnitude higher than that of WAR/PANI. The surface morphology of the coatings after immersion in 3.5% NaCl solution also demonstrated that the WAR-PANI had good corrosion resistance performance, which displayed much more promising anticorrosion performance for steel substrate than WAR/PANI physical blend. [ABSTRACT FROM AUTHOR]