Preparation Of Polyaniline/brominated Epoxy Coatings And Its Application In Anticorrosion And Antifouling

Metallic corrosion and biofouling seriously restrict the application of metallic materials.The use of organic coatings that have high anticorrosion and antifouling performance is one of the most efficient strategies to deal with the problems.Herein,the polyaniline/tetrabromobisphenol-A epoxy/epoxy(PANI/TBEP/EP)composite coatings was prepared using EP coating as primer coating,TBEP coating as top coating and PANI as additive.Then,the anticorrosion and antifouling performance of the composite coatings were characterized.Firstly,TBEP coatings,EP coating and TBEP/EP composite coatings were prepared and characterized.The experimental results demonstrated that the optimum molar ratio of TBEP to curing agent MD1041 was 1:1.Attributed to its hydrophobicity and antibacterial activity of bromine atoms,TBEP coating had superior hydrophobic and antibiofouling properties to that of EP coating.While,the electron-withdrawing effects of bromine atoms reduced TBEP polarity,and that induce TBEP coating had low adhesion strength with metals.Combine high adhesion of the EP coating and high hydrophobic and antibacterial properties of TBEP coating,the TBEP/EP composite coatings consisting of EP primer coating(the thickness was40?m)and TBEP top coating(the thickness was 80?m)was prepared.The experimental results indicated that the composite coatings had excellent anticorrosion and antifouling performance.The impedance of the composite coatings was 6.27�10⁹ohm�cm² after being immersed in 95?,12 wt%Na Cl solution for 70 days.Meanwhile,only a small amount of fouling organisms was observed on the surface of the composite coatings after six-week immersion in river.Secondly,PANI/TBEP/EP composite coatings were prepared by adding different amount PANI to TBEP/EP composite coatings.The experimental result indicated that PANI can enhance the coatings'barrier performance,and facilitate formation of a dense passivation layer(Fe₃O₄/?-Fe₂O₃)at the coating/metal interface.Meanwhile,the result also indicated that the optimal dosage of PANI was 2 wt%,and the impedance of 2wt%-PANI/TBEP/EP composite coatings was 5.46�10¹⁰ ohm�cm² after immersed85 days.Attributed to the antibacterial property of doped PANI,PANI/TBEP composite coatings had superior antifouling performance to that of TBEP coating.During the immersion test in river for six-week,the amount of fouling organisms attached at PANI/TBEP/EP composite coatings was very small,which indicated the composite coatings incorporate with PANI had durable and practical antifouling performance.