Study On Preparation And Preformance Of PANI/Muscovite Composites

Microcrystalline muscovite in western Sichuan is a 2M1 layered silicate mineral with excellent properties such as high electrical resistivity,aging resistance and good insulation properties.Polyaniline is widely used in electromagnetic shielding,adsorption and anti-corrosion and other fields because of simple synthesis,good chemical stability and high electrical conductivity.This paper mainly focuses on the preparation of PANI/Muscovite and its corrosion resistance with muscovite and aniline as its main raw materials.In this paper,the muscovite was heat-treated and acid-treated firstly to reduce the force between the muscovite layers.After mixing lithium nitrate?LiNO₃?with muscovite,Li-muscovite was obtained by incubating in muffle furnace at 300°C;cetyltrimethylammonium bromide?CTAB?and muscovite were treated together in80°C aqueous solution to get CTAB/Muscovite.The change of layer spacing was also characterized by XRD.Finally,PANI/Muscovite composites were synthesized using hydrochloric acid or phytic acid as the dopants,ammonium persulfate as oxidant.Finally,the composites of structure,morphology,thermal stability and conductivity analyzed by XRD,FTIR,SEM,TG and four probe method.Electrochemical workstations were used to test the corrosion resistance of composites coated on the surface of A3 steel,and the changes in corrosion resistance were characterization by Tafel curves and EIS curves.The results of the study are as follows:?1?XRD results showed that the muscovite has good stability.After heat holding treatment at 750°C and 80°C 6mol/L nitric acid treatment,and the layers spacing of muscovite was not change obviously.The layer spacing of muscovite increased from1.021 nm to 1.256 nm after treatment by LiNO₃.After treatment with cetyltrimethylammonium bromide?CTAB?,The layer spacing of muscovite further increased to 1.384 nm.?2?FTIR analysis showed that the prepared composites had characteristic absorption peaks of polyaniline and muscovite.Combined with SEM images,it was found that aniline was successfully inserted into muscovite and polymerized between muscovite layers to obtain PANI/Muscovite composite.XRD analysis showed HCl-PANI was synthesized between the muscovite layers,fully spreading the muscovite sheet;the IP6-PANI was synthesized between the muscovite layers and the layer spacing of muscovite was enlarged.?3?TG showed that the thermal stability of PANI/Muscovite composites is more excellent compared to polyaniline because polyaniline between muscovite layers was protected by muscovite sheet.PANI/Muscovite composite material was tested by four probe method.HCl-PANI/Muscovite exhibited excellent electrical conductivity.The electrical conductivity of IP6-PANI/Muscovite composite material is ordinary.?4?Compared to epoxy resin coating,the PANI/Muscovite/EP composite coating has a higher corrosion potential?Ecorr?and a lower corrosion current density?icorr?,and its corrosion resistance has been significantly improved.Corrosion resistance of A3steel surface coating is related to the composite material content in the coating and the mass ratio of aniline monomer to muscovite during the synthesis of the composite material.The coating layer still exhibited excellent corrosion resistance after 15 days of immercing.?5?After being soaked for 15 days,the surface of A3 steel was completely observed by a metallographic microscope.It showed that the A3 steel coated with HCl-PANI/Muscovite or IP6-PANI/Muscovite composite material had better corrosion resistance.