Preparação e Caracterização de Materiais Híbridos de Magnetita/Polianilina por Polimerização in Situ

Abstract

Polyaniline is a conducting polymer that presents interesting electrical properties, because it has a special mechanism called the doping reaction, a transition process from an insulating polymer or semi-conductor to a conductive material. Magnetite is a ceramic material with magnetic properties associated with its cubic structure of spinel type, with AB2O4 as the general formula. These materials have been widely studied due to their characteristic of absorbing the electromagnetic radiation produced by technological innovations. The hybrid polymeric materials with inorganic fillers may show new properties due to different contributions of each compounds. We have developed synthetic routes to produce hybrids of magnetite and polyaniline (PAni), doped with sodium dodecylbenzenesulfonate (DBSA) and oleic acid (OA). After several tests it was possible to establish a route of synthesis, carried out without stirring, defining the best ratios of reagents and purification methods. There were synthesized three groups of materials: Iron Oxide/PAni(DBSA), Magnetite/PAni(DBSA) and Magnetite/PAni(AO). These materials were characterized by X-ray diffraction, IR spectroscopy, Mossbauer spectroscopy, magnetization, transmission electron microscopy (TEM) and thermogravimetric analysis. The reflectivity at microwave frequency range of 8-12 for the GHz also measured of Magnetite/PAni(DBSA), which presented had low levels of radiation attenuation. However, samples of magnetite/PAni(OA) showed considerable radiation absorption, reaching 99,5% at some frequencies, there results showed a promising and was an absorber material of Electromagnetic Radiation (MARE).