Preparation and anticorrosion performance of poly(o-chloroaniline)-nano SiC/epoxy resin composite

Conducting polymers represent a promising application prospect in the field of metal corrosion control. In order to obtain a poly(o-chloroaniline) (POCl)-nano SiC/epoxy resin composite with good anticorrosion performance, hydrochloric acid doped POCl-nano SiC composite modified material was prepared by in situ polymerization method. The structure, composition and morphology of the POCl-nano SiC composite were characterized by FTIR, UV-vis, XRD, TGA, XPS and SEM. The POCl-nano SiC composite modified material was used as the filler, and epoxy resin was used as the film forming substance, hydrochloric acid doped POCl-nano SiC/epoxy resin composite coatings with 3wt%, 5wt% and 8wt% POCl-nano SiC contents were prepared on the carbon steel substrates, and the fracture surface morphologies of the coatings were observed by SEM. Its anticorrosion performances were studied by Tafel polarization curve and electrochemical impedance spectroscopy in 3.5% NaCl solution. The results demonstrates that the POCl-nano SiC/epoxy resin composite coatings whose POCl-nano SiC content is 5wt% shows better anticorrosion performance, with a corrosion rate of 2.78×10^-3 mm/y and the corrosion protection efficiency up to 90.45%. It indicates that the proper amount of POCl-nano SiC as the reinforcing phase of the epoxy resin coating would reduce the pinhole defects of the coating, under the infiltration of corrosion medium, a passivation layer formed on the surface of carbon steel. Nano SiC particles act as a barrier, which was analogous to the fence structure and blocked the penetration of gas molecules and corrosion solution toward metal substrate spatial structurally.