Study Of Polyaniline/Montmorillonite Composites Anticorrosion Coatings

Among conducting polymers, polyaniline (PANI) is a promising material for commercial applications, because of its environmental stability, good processability, and relatively low cost. It can be applied to electronic devices and products such as light-emitting diodes, organic FETs, EMI shielding, secondary batteries, etc. Blends or composites of PANI with other polymers or inorganic materials can provide new synergistic properties that cannot be attained from individual materials. The use of PANI blends(composites) as anticorrosion coatings had been explored as the potential candidates to replace the chromium-containing materials, which have adverse health and environmental concerns. Moreover, the corrosion resistance of PANI coatings seems to extend to scratched areas where bare steel surface is exposed to aggressive environment.1. The progress of conducting polymers, polyaniline, blends or composites of polyaniline and PANI blends(composites) as anticorrosion coatings were reviewed in this part. 185 references were quoted.2. Polystyrene sulfonic acid (PSSA) doped water-soluble polyaniline (PANI)/ montmorillonite (MMT) clay composites were firstly synthesized by intercalation polymerisation in aqueous medium. The results show the composites has a mixed nanomorphology and exfoliated silicate nanolayeis of MMT clay dispersed in the polyaniline matrix. This composites is more thermal stable than that of without clay samples and results in good stable temperature-dependent dc conductivity[ σ dc(T)] as temperature changed.3. The composite anticorrosion coatings of PANI/MMT and waterborne epoxy resin emulsion(EP) were prepared by mixture in aqueous medium, and used for anticorrosion to A3 steel and stainless steel. Electrochemical impedance spectroscopy(EIS) and Tafel plot demonstrated that the PANI/MMT/EP compositecoatings has better anticorrosion properties than PANI/EP, MMT/EP and PAWMMT/EP mixture. It's impedance and corrosion potential is higher and the corrosion current density is lower.4. We firstly prepared composite anticorrosion coatings of PANI/MMT and waterborne fluorocarben emulsion(FC). The results of electrochemical impedance spectroscopy(EIS) and Tafel plot shows PANI/MMT/FC composite coatings has good anticorrosion properties to A3 steel and stainless steel.5. PANtyMMT and vinyl ester of versatic acid(VedVa)-flu?wocarben copolymeric emulsion(PANI/MMT/VF) composite coatings were prepared for the first time to improve the anticorrosion properties of PANI/MMT/FC composite coatings. The results of electrochemical impedance spectroscopy(EIS) and Tafel plot shows PANI/MMT/VF composite coatings has the best anticorrosion properties to A3 steel and stainless steel in this series because of the special structure of VeoVa.