Preparation of polyaniline‐aniline modified silicon dioxide composite with synergistic anticorrosion effect for waterborne epoxy anticorrosive coatings

Abstract

AbstractOwing to environmental friendliness, waterborne coatings have attracted considerable attention for the protection of mechanical equipment. Herein, polyaniline (PANI)‐aniline modified silicon dioxide (ANSiO2) composite was prepared to improve the corrosion resistance of waterborne epoxy coatings through the modification of SiO2 nanoparticles by aniline‐methyl‐triethoxysilane and the subsequent in situ polymerization of aniline (AN). When the molar ratio of AN to ANSiO2 was 6:1, the obtained PANI‐ANSiO2 composite appeared spherical‐planar shape and was able to obviously improve the anticorrosive performance of the epoxy coatings. The impedance value of the PANI‐ANSiO2 composite modified coatings maintained above 108 Ω cm2 after being immersed in 3.5 wt% NaCl solution for 30 days, and the surface of the coating had no corrosion spread after 30 days of salt spray erosion test. The excellent anticorrosive effect of the PANI‐ANSiO2 was mainly attributed to not only the filling of the defective parts of the coatings by hydrophobic ANSiO2 but also the formation of passivation layer on the coating surface by PANI to impede electrochemical corrosion reaction. The preparation method in this work is facile, low‐cost, and easy produced on a large scale, and the environment friendly high‐anticorrosion coating shows great application potential in the field of metal protection.