Studies On Preparation And Properties Of Polyaniline Derivatives And Inorganic Matters/Polyaniline Nanocmposites

In this paper, description relating to the history of development, synthetic methods, and mechanism of polymerization, chemical structure, doped methods and mechanisms of polyaniline were reviewed. The effect of reaction conditions on chemical structure of polyaniline were discussed in detail. One of the key problems related to the application of polyaniline is its poor processability due to the rigid-rod macromolecular chains and strong interchain interactions. Several approaches were mentioned to solve the problem and also the preparations of nanocomposites as polyaniline/inorganic materials were described. The applications of polyaniline in recent years were concluded from eight different aspects. Modification to polyaniline was achieved successfully by copolymerization of N-substituted aniline and aniline, ring-substituted aniline and aniline. As well, preparation of the nanocomposites composed of attapulgite and polyaniline, and nano silica and polyaniline were studied in detail in this paper. The research direction on polyaniline in the near future was also previewed.Homopolymerization of N-substituted anilines or their copolymerization with aniline resulted in improved solubility while decreased conductivity of the polymers obtained. Ring-substituted polyaniline had a lower rigidity compared to polyaniline and the substituents could weaken interchain interactions between polymer chains, resulting in increased solubility. And also ring-substituted aniline could hinder the side reactions happened on the ring during polymerization procedure, which was benefit for formingÏ€-electron conjugated system. Besides these, the nanocomposites composed of polyaniline and inorganic materials were prepared. The solubility and conductivity of the polymers and nanocomposites were studied systematically. Techniques of FT-IR, UV-Vis, XRD, ESR, TEM, SEM, TGA and DSC were applied in this paper.(1) Monomers as N-β-cyanoethylaniline and N-phenylglycine copolymerized with aniline by chemical oxidative method, respectively. With introducing different molar ratio of aniline to the comonomers, the conductivity, solubility and spectral absorptions properties of the copolymers appeared a few of regularity. The copolymers had better solubility while poorer conductivity than pure polyaniline. It can be provided with some information on studying of the relationship between physical properties and chemical structure by introduction of the electron-withdrawing groups to the nitrogen of aniline. These polymers prepared in this paper were looking forward to be used as semiconductor, anticorrosion and antistatic materials.(2) 2-Aminobenzyl alcohol and aniline as comonomers were polymerized firstly by chemical oxidative method in this paper. The copolymer showed some regularity on conductivity, solubility and spectral absorptions properties. The hydroxyl groups on the polymer chains were looking forward to be used as a new reaction site to prepare other conductive polyaniline derivatives.(3) The nanocomposites based on polyaniline and attapulgite (including organic attapulgite) were obtained by in situ and emulsion polymerization, respectively. With various weight of attapulgite or organic attapulgite added, the conductivity and heat-resistance of the composites showed special regularity. They were looking forward to be applied in the field of ceramic, fire-resistance, low gas permeability and so on.(4) Composite of polyaniline coated nano silica was firstly prepared by chemical method. There existed chemical effect between SiO₂ and polyaniline but not physical absorption, leading to the composite exist more stable in the environment. Also the conductivity of it were studied. The composite was wished to be used as heat-resistance and anticorrosion materials.