Electrodeposition And Anticorrosion Property Of Pernigraniline And Doped Polyaniline

Corrosion is the destructive result induced by chemical or electrochemical reactions between metal and its surrounding environment. And it has caused enormous economic cost, disastrous accidents and even seriously affected the safety and development of society. So people continually seek new anticorrosion material. As polymer materials, polyaniline (PANI) has much superiority, such as outstanding anticorrosion properties, excellent stability, easy synthesis. Moreover, polyaniline attracts extensive attention due to its various pernigraniline, and the property of interconverting with each other under certain conditions.In this paper, doped polyaniline and pernigraniline were prepared by cyclic voltammetry and galvanostatic polarization onto stainless steel surface, respectively. The anticorrosion properties of them were studied by electrochemical impedance spectroscopy and polarization curve.Firstly, doped polyaniline was deposited on steel from aniline containing oxalic acid solution by cyclic voltammetry, and characterized by FT-IR. The effect of the parameters on corrosion protection of polyaniline was studied, such as scan rate, scan cycle and sodium molybdate. The results show that anticorrosion property of polyaniline is excellent, and the corrosion potential in0.5M H2SO4solution shifted into much higher potential values, at around+0.77V, when the scan rate was200mV/s. Corrosion protection of polyaniline is been enhanced with increasing of scan rate. Its corrosion potential remains300mV higher than that of stainless steel after immersed in3.5%NaCl solution66days when the scan cycle was60. Anticorrosion property of polyaniline is also enhanced with increasing concentration of sodium molybdate. Corrosion current density reduced to quarter of stainless steel when concentration of sodium molybdate was0.08M. And the PANI-MoO42-coating is able to offer higher corrosion protection in comparison to that of pure PANI coating.Secondly, pernigraniline prepared by galvanostatic polarization from NaOH solution, characterized polyaniline by FT-IR and energy spectrum, and its anticorrosion properties was studied by electrochemical test. The results show that the anticorrosion property of polyaniline is preferable when polarization current density was2mA/cm2and polarization time was4.5～6min. Finally, sulfate reducting bacteria (SRB) are cultured in laboratory. The corrosion protection of PANI and the surface morphology of polyaniline immersed in SRB solution for14days were studied. The results indicate that polyaniline has antibacterial property against SRB and decreases the corrosion current density of stainless steel.