Effects of polyaniline content in chlorrub‐based coatings on corrosion protection of steel

Abstract

Corrosion protection of steel coated with chlorrub resin containing polyaniline has been studied in 3% NaCl by electrochemical impedance spectroscopy (EIS). Polyaniline was prepared by oxidative polymerization of aniline using ammonium persulphate in HCl medium. Using the synthesized polyaniline, paints were prepared using chlorrub resin with 1, 3, and 5% polyaniline. The variation of resistance and capacitance of the coating with time has been found out be EIS. The study has shown that the polyaniline content of 1% is able to offer sufficient protection of steel in neutral media and usage of higher percentage of polyaniline does not have beneficial effect.

High Performance Self-Healing Epoxy/Polyamide Protective Coating Containing Epoxy Microcapsules and Polyaniline Nanofibers for Mild Carbon Steel

“…For microcapsules, this may be explained by the fact that the healing agent delivered to the damaged region is inadequate when the concentration of microcapsules is too low, while the coating porosity increases and density reduces when the concentration of microcapsules is too high. For PANI, it can cause significant effect in corrosion protection at low concentration of 1.0–3.0% by weight and it is able to offer sufficient protection for steel. − This may be because PANI nanofibers have small size and uniform morphology, as shown in Figure . They can be dispersed uniformly in coating matrix and intertwined with each other to form a dense network, which allows the distribution of PANI nanofibers to have excellent continuity (Figure ).…”

“…Organic coatings containing PANI have been increasingly applied for corrosion protection because of their excellent corrosion protection performances. − PANI could induce a passivation oxide layer between the metal and the coating to protect the metal beneath the oxide layer from further corrosive attack. Recent studies show that PANI dispersed at the concentration of 1–3% by weight in various coatings can cause significant improvement in metal protection, and usage of a higher percentage of PANI has no beneficial effect. − It is also reported that the coatings containing PANI nanofibers have superior protective performance to that of coatings containing conventional PANI …”

Corrosion Protection Mechanism of Polyaniline Blended Organic Coating on Steel

“…The experimental details were given in earlier publications. 16,17 Preparation of polyaniline containing epoxy-coal tar paint.-The epoxy resin solution was prepared by dissolving solid epoxy having an epoxy equivalent weight of 450-550 in xylene. The coal tar was added to the epoxy resin and mixed thoroughly.…”

“…1,2 Besides, several studies have shown that PANI-containing coatings are able to protect steel more effectively due to its passivation ability. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Recently, it is shown that the addition of a small amount of titanium powder in an epoxy-coal tar coating system is able to improve the corrosionresistance property of the coating. 23 Furthermore, it has been reported that the dopants in PANI play an important role in corrosion protection due to the formation of an iron-dopant secondary layer.…”

Development of nanostructured polyaniline dispersed smart anticorrosive composite coatings

“…28 As the size of the dopant increases, the strength of the iron/dopant complex film increases; this improves the corrosion protective efficiency. [29][30][31][32][33] Moreover, the presence of nanoparticle size (40 nm) and uniform dispersion of the MO-PANI in COPU helps in the formation of a well-adherent, uniform, dense, and continuous passive film which impedes the penetration of the corrosive ions to the metal substrate and inhibits MS from the attack of the corrosive species. 28…”