Highly Durable and Novel Anticorrosive Coating Based on Epoxy Reinforced with Poly(Aniline-co-Pentafluoroaniline)/SiO 2 Composite

The paper presents the development of high strength anticorrosive coating based on epoxy formulated with poly(aniline-co-2,3,4,5,6 pentafluoro aniline)/SiO2 composite. The composites display outstanding barrier properties against corrosive ions. SiO2 particles were found to significantly improve the microstructure of the coating matrix and thus enhanced both the anticorrosive performance and mechanical property of the epoxy coating. Electrochemical characterization was carried out in 3.5 wt% NaCl which show a remarkable improvement in the corrosion resistance of epoxy coating with addition of copolymer composites. The high pore resistance indicates the slow migration of ions into the metal and coating interface. Remarkable reduction of corrosion current density from 84.0 µA/cm2 in epoxy coating to 2.0 µA/cm2 in epoxy with copolymer/SiO2 composite coating was observed. Salt spray test of coated mild steel was carried out in 5.0 wt.% NaCl solution for 120 days as per ASTM B117 method. Electrochemical studies and salt spray test indicate the superior anticorrosive performance offered by the co-polymer composite under accelerated test conditions. Mechanical testing such as bend test, Taber abrasion resistance and cross cut adhesion test of epoxy formulated copolymer composite were carried out to evaluate the durability and adhesion performance of coating on the metal surface. The results show that the coating based on copolymer/SiO2 composites has improved corrosion resistance performance as well as mechanical properties more than several times as compared to epoxy coating. Better mechanical and barrier properties of the epoxy based copolymer composite were able to make the coating highly durable and anticorrosive in aggressive environment. Moreover, the significantly improved corrosion protection and mechanical strength is attributed to the synergistic effect of SiO2 particles and pentafluoro aniline in copolymer chain. We expect that the present concept opens new ways to prepare conducting polymer composite based epoxy coating for anticorrosion and other functional purposes.