Preparation And Corrosion Resistance Properties Of Polyaniline And Its Derivatives Composite Coatings

Conducting polymers represent a promising application prospect in the field of metal corrosion protection. Among the conducting polymers, polyaniline becomes the focus in the anticorrosion coating fields because of its excellent corrosion resistance. In this paper,the corrosion resistance of epoxy resin and polyamide system with polyaniline or poly(o-toluidine)(polyaniline derivatives) composite materials as fillers on steel substrate have been studied. The contents and results are as follows:Polyaniline/nano Si C composite materials were prepared by in situ polymerization method, the composite materials and epoxy resin and polyamide system by blending to prepare the polyaniline/nano Si C/epoxy composite coating onto the steel substrate surface.Its corrosion resistance was studied by open circuit potential, polarization curves and electrochemical impedance spectroscopy in 3.5% Na Cl solution, and the corrosion resistance and adhesion effects of polyaniline and nano Si C to composite coating were explored through immersion experiments in 3.0% Na Cl solution. The results showed that polyaniline/nano Si C composite as the reinforcing phase of the epoxy coating, under the infiltration action of corrosive medium, its can activate that polyaniline forming a passivation Fe2O3 layer on the carbon steel substrate; nano Si C particles act as a fence structure that block the penetration of corrosive medium in the coating, and enhanced the barrier properties of epoxy coatings.Poly(o-toluidine)/polyaniline copolymer materials were prepared by in chemical oxidation polymerization method, the solubility tests found that the solubility of the copolymer is higher than the homopolymer. The corrosion resistance of polyaniline/epoxy composite coating, poly(o-toluidine)/epoxy composite coating were researched by electrochemical test and salt water immersion test as well as poly(o-toluidine)/polyaniline composite coating, the results showed polyaniline/epoxy composite coating’s corrosion resistance was the worst. This is because the macromolecular poly(o-toluidine)/polyaniline copolymer dispersed uniformly in the epoxy coating, improved the adhesion of the metal substrate and the passivation effect of the metal surface, it has excellent corrosion resistance.Poly(o-toluidine)/nano Zr O2 composite materials were prepared by in situ polymerization method, through the spectrum analysis confirmed that the interaction existent between nano Zr O2 and poly(o-toluidine), and poly(o-toluidine)/nano Zr O2 composite materials have obtained a good composite effect in structure, crystal,morphology, thermal stability and particle size respect. The poly(o-toluidine)/nano Zr O2/epoxy composite coating by electrochemical test, water absorption and salt water immersion test found, compared with poly(o-toluidine)/epoxy composite coating, the addition of nano Zr O2 particles enhances the barrier properties of the coating,nanoparticles act as a fence structure that block the penetration of corrosive medium in the coating.