Keywords: Polyaniline; nanofibre; primer layer; protective coating systems; FE-SEM result; salt spray test; EIS measurements; protective performances

Abstract

The paper presents some results of comparative investigation on the efficiency of polyaniline (PAni) finely dispersed in polyvinyl butyral as primers in different anticorrosive painting systems. The PAni nanofibres were used for the protective coating purpose. The PAni have various dopants such as inorganic acids (HCl in ES-M samples, H3PO4 in ES-P samples) and organic acid (p toluene sulphonic acid in ES-T samples). The nanostructures of the PAni samples were proved by FE-SEM results. We have investigated comparatively 3 paint systems having the cover coat of polyurethane with different primers: L1 (with ES-M as active component); L2 (with ES-P) and L3 (with ES-T) using salt spray test and electrochemical impedance measurements. Results of salt spray test showed that all the systems having PAni as primers resist over 1440 h (60 cycles). Results of EIS showed that samples using L3 primers gave the highest protective efficiency (with |Z| 0,1Hz = 108 Ω.cm2 and its open circuit potential value reached –34.8 mV/SCE after 63 days immersed in 3% NaCl medium). All the research results demonstrated clearly that PAni nanofibres could be a very good component for primer coating systems.