Soluble Aniline Polymer Synthesis And Carbon Steel Corrosion Inhibition Performance Study

In industrial, pickling is a convenient, highly efficient and low-cost process for eliminating the corrosion and protecting the metals. However, pickling may destroy the material and environment. Therefore, it is necessary to add corrosion inhibitors in acid solution to restrain the corrosion of metals in acidic media, to improve the pickling effect, and to protect the equipment for extending its using life. In the acidic medium, polyaniline and its derivatives may adsorb on the surface of metals by physical or chemical adsorption because they contain O, N et al polar groups in the structure. While the C and H et al non-polar groups form a hydrophobic protection film, which protect good corrosion inhibition effect.In this dissertation, several types of soluble polyaniline and its derivatives were synthesized through chemical method. The properties and the applications were conducted by the corrosion inhibition effect of them on the carbon steel in hydrochloric acid solution.(1) A poly(aniline-formaldehyde) resin, which can dissolve in acid solution, was synthesized by the polymerization of aniline and formaldehyde. The obtained poly(aniline-formaldehyde) was added in 1.0 mol/L of hydrochloric acid to use as a corrosion inhibitor for Q235 carbon steel. The electrochemistry measurements and weight loss test demonstrated that the inhibition efficiency achieves much higher than 90%. By varying the ratio of aniline and the formaldehyde in the polymerization process, the synthesized structure of the resin changed gradually from the linear shape to the cross-linking form. Moreover, it was found that as the concentration of the inhibitor increases, the inhibition efficiency increases gradually. However, when the poly(aniline-formaldehyde) concentration was increased to the higher value, the inhibition efficiency drop due to the passivation effect of the metal surface.(2) In the presence of non-ionic surfactant OP-10 and P123, the aniline and anthranilic acid were polymerized to water-soluble polyaniline and polyanthraniline. Using these polymers as the corrosion inhibitors to investigate the anti-corrosion effect of the Q235 mild steel, it was found that the water-soluble polyaniline and poly(o-anthranilic acid) are good corrosion inhibitors. The inhibition efficiency improved gradually with the content of OP-10 and P123 increases in the polymerization.