Research And Development Of Micro-nano Conductive Polyaniline Composite Particles And Waterborne Anti-corrosion Coatings

It is urgent to solve corrosion problems, as metals are easy to be corrupted in acid circumstance and sea water. Metal corrosion causes great economic loss and damage to industry and society. And coating is the most important and economical method of all anticorrosive methods. However the anticorrosion of the traditional coating is not very ideal due to the limit of material properties and technology. And a lot of the coatings contain heavy metals that induce the environment polluted. So research and development of a green corrosion inhibitor becomes a focal point of the corrosion protection field.Conductive polyaniline as new material of functional polymer makes itself a focus because of its simple synthesis methods, excellent environmental stability and wide application. Polyaniline as a corrosion inhibitor has no any environmental side-effect compare with other conventional corrosion inhibitors, such as chromate, and it is a green corrosion inhibitor accord with times and science development. But it has poor processability because of its rigid structure. In this paper, core-shell structure is applied to overcome the defects confining the application of polyaniline.First, Poly(methyl methacrylate-butyl acrylate-acrylic acid) [P(MMA-BA-AA)] /polyaniline (PANI) core-shell complex particles were synthesized with a two-step miniemulsion polymerization method with P(MMA-BA-AA) as the core and PANI as the shell. The first step was to prepare P(MMA-BA-AA) latex particles as the core via miniemulsion polymerization. The second step was to prepare P(MMA-BA-AA) /PANI core-shell particles. The aniline monomer was added into the mixture of water and core particles. The aniline monomer could be attracted near the outer surface of the core particles. The polymerization of aniline was started under the action of APS. The final product was the desired core-shell nano-particles. At the same time, using 4-styrenesulfonic acid sodium salt (NaSS) as sulfonation monomers, sulfonated polystyrene microspheres were successfully prepared by dispersion polymerization. Using this kind of sulfonated PS spheres as core templates, PS-polyaniline(PANI) core-shell microspheres were produced. After removing the cores, uniform hollow conductive polymer microspheres were obtained. TEM, SEM and FTIR are used to character the resulting products. The optimized conditions for core-shell or hollow particles preparation were decided preliminary.Then waterborne bisphenol A epoxy resin emulsion was prepared by phase inversion. At last, a series of polyaniline/epoxy anticorrosive coatings were prepared, and theirs anticorrosive performance in 3.5% NaCl solution was studied. The outcome shows that the anticorrosive coatings contain PANI core-shell particles have good anticorrosion property.