Study On The Synthesis, Characterization And Application Of Nanopolyaniline

Conductive polyaniline as a new material of functional polymer is given more and more attention by scientists because of its simple synthesis methods, particular doping mechanism, excellent environmental stability, as well as wide application. However, the properties of infusibility and insolubility are the obstacles of its application. Nanomaterial has the special physical and chemical properties. Introducing nanotechnology into the synthetical technology of polyaniline will improve its fusibility and solubility remarkably. The nanoparticles of polyaniline with high conductivity were synthesized by the technology of microemulsion polymerization, applying the composite emulsifier made up of certain emulsifier and proton acid. The best conditions of synthetical technology were determined by orthogoral experiment, and polyaniline`s conductivity, microstructure, crystallization, thermal stability, particle size, particle dispersion and others properties were analyzed and characterized by modern testing methods, such as IR, XRD, TGA, AFM, TEM, UV, and so on. Compared with non-nanopolyaniline synthesized by conventional emulsion polymerization, nanopolyaniline has the narrow and uniform distribution of particle dimension and the diameter of particle is about 4-5nm,and the conductivity reaches 3.2S·cm-1, which is more than 100 times higher than that of nanopolyaniline;Moreover, it has higher solubility in conventional solvent and the solubility reaches 95% in N-methyl pyrrolidone;what`s more ,it has higher crystallinity and more uniform crystal proved by XRD, apparent blue shift indicated by UV, which makes it possible to prepare transparent conductive composite films. Based on the experimental condition of lab, the best technical conditions were enlarged and the defect was found that a large quantity of emulsifier was used in the process of practical production, which brought about the difficulty of separation and purification in the processing. For this reason, the mass ratio of monomer and emulsifier was increased and acetone was effectively reclaimed from the filtrate for circulatory use, which resolved the difficulty and greatly reduced the producing cost.Compared with the present polyaniline merchandise, the nanopolyaniline synthesized by this improved technology has evident advantages in certain property, such as particle size, conductivity ,solubility,synthetical cost and so on, which can be applied widely. The application of nanopolyaniline in anticorrosion paint was also studied. Meanwhile, the composite film of nanopolyaniline-polyvinyl acetate was produced by microemulsion polymerization, which has high conductivity and better environmental stability.