Effect of different oxidation states of polyaniline on anticorrosion performances of modified zinc rich primer
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© 2016 by NACE International. The objective of this work is to improve the anticorrosion performance of a commercial zinc rich primer (ZRP) by using an intrinsically conductive polymer polyaniline (PAni). Different states of PAni including nonconductive emeraldine base (EB) and conductive emeraldine salt (ES) were added to ZRP, to study the effects of the different oxidation states on anticorrosive performance. EB is electrically neutral while doped (protonated), and the resulting ES form is highly electrically conductive. The synthesized PAni additives and coated panels were characterized by X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and other normal coating evaluation techniques. The anticorrosion performances were studied in 3.5 wt. % NaCI solution by electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP). The results show that the addition of a small amount of conductive PAni to ZRP slowed the activation process of zinc particles and further improved the cathodic protection effect. It also provided better barrier performance compared with the commercial ZRP. The nonconductive PAni EB accelerated the activation of zinc particles, and the formed zinc oxide products were compact and provided better barrier performance than the commercial ZRP.
author list (cited authors)
Li, X., Yang, D., & Castaneda, H.