Reactive doping of PAni-CSA and its use in conducting coatings

Conductive coatings have been studied for static dissipation and microwave absorbing materia ls based on blends of polyurethane and polyaniline. Conducting polymers have been widely used because of their lower density as well their good environmental stability as in the case of polyaniline (PAni). The doping process of polyaniline, which turn it conductive, is an important stage for the coating performance. For this, sulfonic acid is normally used because of the thermal behavior offered to the final material. Camphor sulfonic acid (CSA) has been used because of the metallic characteristic gave to the polyaniline, increasing the conductive property of the polymer. For this purpose, the polyaniline was doped by reactive processing in a rheomix coupled to a torque rheometer using different ratios of the acid (PAni:CSA) and temperatures (80, 90 and 100 oC). Aqueous solution doping was also used in the ratio of 1:2 of PAni:CSA, aiming to investigate the influence of the different methods of doping on the PAni characteristics and, consequently, on the conductive coatings performance. Thermal analyses of the processed materials showed that the PAni doped by both routes, reactive and solution processing, showed similar behavior. X-ray diffraction analyses showed a semicrystalline structure of the PAni-CSA doped by reactive processing using high CSA concentrations and temperature. It was also observed that the doping process affects the dispersion of the components into the conductive coatings. Microwave absorptio