THE ROLE OF COUNTER ANIONS IN ANTICORROSIVE PROPERTIES OF SILICA-POLYPYRROLE COMPOSITE

Silica/Polypyrrole (SiO2/PPy) composites were synthesized in the presence of different counter anions as oxalate (Ox), benzoat (Bz) and dodecyl-sulfate (DoS). The morphology and properties of composites were characterized by FTIR, EDX, SEM, TGA and CV method through the two-point-electrode. The synthesized composites were loaded in polyvinylbutyral (PVB) to develop coating for mild steel substrates. A comparative study of the corrosion protection efficiency of carbon steel coated with PVB and PVB containing composites was evaluated by measurement of open circuit potential (OCP), Tafel polarization and electrochemical impedance spectroscopy (EIS). It was found that SiO2/PPyOx could provide much better protection, with the lowest current density (4.81×10-8 A.cm-2 and highest impedance modulus (6.25×10-8 Ω.cm-2) when compared with SiO2/PPyDoS and SiO2/PPyBz due to the small size and inhibitive ability of oxalate anion