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Novel TiO2-PANI core-shell nanocomposite, prepared by in situ oxidative polymerization of aniline in the presence of TiO2 nanoparticles surface modified with vitamin B6, was used to reinforce epoxy resin. The size of prepared TiO2 nanoparticles and TiO2-PANI nanocomposite were determined by a transmission electron microscopy (TEM). The surface modification of TiO2 nanoparticles was confirmed by FTIR and UV-vis spectroscopy, while the morphology of PANI and TiO2-PANI nanocomposite was investigated by scanning electron microscopy (SEM). The influence of TiO2-PANI nanocomposite on glass transition temperature, dielectric and dynamic mechanical properties, thermooxidative stability, mechanical and anticorrosion properties of epoxy based nanocomposites was investigated and compared to the properties of epoxy/PANI nanocomposites. It has been observed that the glass transition temperature of epoxy resin increases after introduction of PANI and TiO2-PANI nanocomposite, as well as with increasing their content. Prepared nanocomposites exhibited higher value of dielectric constant than pure epoxy resin. Epoxy based coating containing TiO2-PANI nanocomposite showed lower dielectric loss, higher hardness and better anticorrosion properties than pure epoxy resin and epoxy/PANI nanocomposite. (C) 2016 Elsevier B.V. All rights reserved.

The protective abilities of composite coatings based on electrochemically and chemically formed polyaniline powder against the corrosion of mild steel were investigated. A polyaniline powder has been prepared in the form of an emeraldine base and benzoate salt through chemical dedoping and doping. The composite coatings using polyaniline powders, which were obtained through different routes, and base coatings, which were not corrosion-resistant, with different formulations were prepared and applied on mild steelsamples. The corrosion was investigated using an electrochemical impedance technique in 3% NaCl, andthe atmospheric corrosion was assessed in a humidity chamber. Emeraldine-benzoate salts, which area chemically synthesized polyaniline, offer the best protection with an optimal polyaniline concentration of approximately 5 wt%. The different corrosion behaviors were assessed relative to the presence of aniline oligomers in the samples after characterization using UV-vis spectrophotometry. Upon comparison between the corrosion behavior in 3% NaCl with commercial primer paint for iron and that with apaint containing 5 wt% PANI, the composite coating has superior anticorrosion characteristics. The mech-anism for the protection of mild steel from corrosion through composite polyaniline coatings was also considered. © 2014 Elsevier B.V. All rights reserved.

The polyaniline thin film electrode and powder have been synthesized on graphite electrodes from 0.5 M hydrochloric acid solution under galvanostatic conditions. The water insoluble and acetone soluble polyaniline mass fractions of the powder, as well as the polymerization efficiency, based on the emeraldine salt have been determined. The morphology of the obtained emeraldine salt powder has been investigated by the optical microscopy.

The corrosion behavior, sorption characteristics and thermal stability of epoxy coatings electrodeposited on mild steel (MS) and mild steel with electrochemically deposited polyaniline (PANI) film were investigated in 3% NaCl solution using electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA). Electrochemical deposition of PANI film on mild steel was performed from aqueous solution of 0.5 M sodium benzoate and 0.1 M aniline at constant current density of 1.5 mA cm −2 . Epoxy coatings on mild steel and mild steel with PANI film were deposited at constant voltage. It was shown that during initial time of exposure to 3% NaCl, PANI/epoxy coating system on mild steel has lower values of pore resistance (obtained from EIS), greater amount of absorbed water and lower thermal stability (obtained from TGA) which indicate more porous structure comparing to epoxy coating on mild steel. During prolonged exposure to 3% NaCl, PANI/epoxy coating system exhibited increased corrosion protection of mild steel comparing to epoxy coating due to the barrier effect of PANI film and the influence of the dissolved molecular oxygen on cathodic and anodic reaction. Differences between corrosion behavior of epoxy coated and PANI/epoxy coated mild steel in acid and neutral solutions has been discussed.