Performance of Polyaniline/TiO2 Nanocomposites in Epoxy for Corrosion Resistant Coatings

In recent years it has been shown that electrically conducting polymers such as polyaniline (PANI) in integrated coating applications are able to protect steel from corrosion due to formation of passive oxide layer on the metal surface. In this report, we present the comparative corrosion protection performance of the coatings containing nanopolyaniline and polyaniline/TiO2 nanocomposites (PTC) on carbon steel in epoxy binder. The PANI was prepared by emulsion polymerization method of aniline using ammonium persulphate. The synthesized polymers were characterized by FTIR, X-ray diffraction (XRD) and the particle size and surface morphology were analyzed by transmission electron microscopy technique. The corrosion protection performance of the coatings was evaluated by weight loss measurement in different corrosive media for 960 h and surface morphology was examined by scanning electron microscopy. Furthermore, immersion test was carried out in an aqueous solution of NaCl for 720 h and corrosion of the panels was monitored by visual inspection. The water adsorption in the prepared coatings was also studied. In our study, it was observed that the PANI/TiO2 in epoxy coating showed better physico-mechanical properties as compared to nano-PANI containing coatings. The PANI/TiO2 could be useful as an adhesion promoter and corrosion inhibitor.