Preparation and Corrosion Inhibition of Phytate-doped Polypyrole (PPy)/nano-SiO₂/Epoxy Resin Long Life Anti-corrosion Coating

The phytate-doped polypyrole (PPy)/nano-SiO2 particles with a core-shell structure were synthesized by chemical oxidizing method using FeCl3 as oxidant, sodium phytate (IP6) as dopant, and nano-SiO2 as dispersion medium. The influences of oxidant and dispersant dosage and reaction temperature on the doping ratio were investigated by ICP-AES technique. The structure, morphology and stability of the prepared phytate-doped PPy/nano-SiO2 particles were characterized using TEM, XRD and TG techniques. The effect of the prepared long-life anti-corrosion coating on the corrosion of Q235 steel in 1.0 mol/L HCl was investigated by EIS measurement. The results show that the silica nano-particles were coated with polypyrole uniformly. The phytate-doped PPy/nano-SiO2 particles with high stability and core-shell structure were obtained. The high doping ratio of 98.53% was achieved under optimized reaction conditions: n(Py)∶n(FeCl3)=2∶1,m(SiO2)∶m(Py)=1∶5 and reaction temperature of -5 ℃. The long-life anti-corrosion phytate-doped PPy/nano-SiO2/epoxy resin coating prepared using phytate-doped PPy/nano-SiO2 particles as functional component and epoxy resin as main film forming material inhibited the corrosion of Q235 steel in 1.0 mol/L HCl solution effectively.