Evaluating protection performance of zinc rich epoxy paints modified with polyaniline and polyaniline-clay nanocomposite

Cloisite 30B nano clay was delaminated in the presence of aniline monomers using supercritical CO2 (ScCO2) process. Rapid mixing polymerization of aniline monomers was done in supercritical CO2 to produce exfoliated polyaniline clay (PAniC) nanocomposites with high barrier properties. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and XRD analysis have been used to characterize morphology and structure of the synthesized products. The synthesized products were added to a commercial zinc rich epoxy primer to improve its initial barrier properties. Barrier properties of unmodified and modified primers were then studied by determining water vapour transmission (WVT) rate of their free films, free corrosion potential (E-corr) and electrochemical impedance spectroscopy (EIS) measurements of carbon steel coated panels. Results showed that samples modified with PAniC nanocomposites had better barrier properties compared to PAni modified and original primers. The coating resistance of PAniC modified primer was at least one order of magnitude higher than other primers at the begining of immersion. After one year of immersion, the coating resistance of original, PAni modified and PAniC modified primers were found to be 267, 1610 and 5540 ohm, respectively. (C) 2014 Elsevier B.V. All rights reserved.