Synthesis And Corrosion Inhibition Performances Of Several Aniline Derivatives To Mild Steel

The corrosion protection is a main topic in the area of material science and engineering now. Using inhibitors is a convenient, effective and economical method, and organic amines have been widely used in industrial acid pickling processes. But the relation between the molecular structure and inhibition effect remains unclear, and more researches are still necessary. To seek an effective method for improving the inhibitive performances of organic amino compounds, two water-soluble polyanilines and a gemini aniline derivative were prepared, and their inhibitive performances to Q235 mild steel in 1 mol/L HCl were investigated by weight loss measurement, potentiodynamic polarization and electrochemical impedance spectroscopy.As the results show, the solubility of insoluble polyaniline was largely improved by the copolymerization of aniline and 2-methoxyaniline-5-sulfonic acid(MAS), as well as the inhibition efficiency. And the solubility improvement of polyaniline was found limited by the doping of dodecyl benzenesulfonic acid. It shows that the improvement of solubility is the key to improve the inhibiting performances.The better soluble gemini aniline derivative, 1,3-bisphenylamino-isopropanol, shows largely improved corrosion inhibition efficiency compared with aniline. It proves the effectiveness of improving the inhibitive performances by the method of gemini derivation and consequently the elevated charge density of polar groups. Furthermore, the synergistic effect of various concentrations of anodic surfactant sodium dodecylsulphate(SDS), cationic surfactant tetrabutylammonium bromide(TBAB) and nonionic surfactant Triton X-100(TX-100) was also investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. It was found that SDS and TX-100 show synergistic effect while TBAB shows antagonistic effect.