Study On The Preparation And Corrosion Inhibition Properties Of Water-soluble Polyaniline

Due to unique doping mechanism,conducting polymer polyaniline?PANI?showed excellent physical chemical and electrochemical properties.It has a broad application prospect,and become a hot research topic in the field of conductive polymer materials recently.Many new technologies and applicationshad been developed based on the PANI.But the rigid structure of polyaniline make its dissolving capacity and applications limited,so the synthesis of polyaniline and its derivatives dissolving capacity and practical application have many problems to be solved.This paper uses emulsion polymerization,which is based on aniline monomers,ammonium persulfate as the oxidant,macromolecule organic sulfonic acid as the doping acid.Finally Polyaniline doping modification is achived.The water-soluble dopped polyaniline was prepared successful,the synthetic product was dark green powder.From the characteristic functional groups of quinoid structure and benzene structureof the synthetic products showed by infrared spectrum,we can see that the aniline had been effectively aggregated and in 1037.39 cm^-1occurred the characteristics of vibration absorption peak of the sulfonic acid group.Solubility experiment show that polyaniline prepared by emulsion polymerization method has good solubility in water.In this paper,the corrosion performance of water-soluble PANI for carbon steel in acid NaCl corrosive medium.had been researched.By soaking experiments,the corrosion performance of polyaniline prepared in different ratio of aniline monomers and dopping acid was studied by electrochemical impedance technique.Thenthe influence of many factors such as polyaniline concentration,experimental temperature,soaking time on theinhibition efficiency has been researched.By the potentiodynamic polarization curve,electrochemical impedance spectroscopy,canning electron microscope and adsorption isotherm model,a preliminary discussion on inhibition mechanism of water soluble doped polyaniline has been conduted.In order to explore the inhibition mechanism ofwater soluble polyaniline deeply,this paper compared the inhibition performance of PANI for carbon under the different corrosion medium to obtain the influence of chlorideion in the acidic solution.In acidic NaCl corrosion medium,water soluble doped polyaniline has obvious inhibition effect on carbon steel.The inhibition efficiency of water soluble polyaniline for carbon steel was influenced by many factors,such aspolyaniline concentration,experiment temperature and soaking time.Water soluble doped polyaniline was a kind of interface corrosion inhibitor,mainly inhibited the cathodic reaction process of carbon steel corrosion.The inhibition mechanism of water soluble doped polyaniline was the adsorption of the PANI on the carbon surface.The surface adsorption process was accompanied by chemical adsorption and physical adsorption process,which was satisfied with Langmiur isothermal adsorption model.Thermodynamic calculation shows thatthe polyaniline is spontaneously adsorbed on the carbon steel surface.The adsorption process on the surface of the carbon steel accompanied by physical adsorption and chemical adsorption process,is associated with exothermic process of entropy decreasing.The existence of chlorine ion in acid NaCl corrosive medium is more conductive to improve the polyaniline corrosion inhibition effect on carbon steel in acidic solution.