Preparation and characterization of composite polyaniline/poly(vinyl alcohol)/palygorskite

Abstract

The preparation of composites occurred by insertion of organically modified molecules, using quaternary ammonium salts—Cetremide (cetyl trimethyl ammonium bromide, CTAB) and Genamim (cetyl trimethyl ammonium chloride, CTAC)—in the fibrous structure of the palygorskite clay (PALY). For the preparation of PANI/PVA (polyaniline/poly(vinyl alcohol), PANI/PVA/PALY, PANI/PVA/PALY-CTAB, and PANI/PVA/PALY-CTAC films, the “casting” technique was used, and they were characterized by XRD, FTIR, SEM, TG/DTG, and DSC. The XRD and FTIR data suggest that there was the incorporation of characteristic groups of the ammonium salts was incorporated on the clay. The TG/DTG curves showed that the decomposition occurred with natural and organophilic PALY showing a thermal stability profile. The incorporation of PALY to the blend PANI/PVA affected the thermal profile, and the DSC curves of the PANI/PVA/PALY suggest that the incorporation of polymers in the PALY structure decreases the crystalline fraction of the material. Through electrical impedance spectroscopy with alternating current, we observed that the blend of composites PANI/PVA with clay PALY-CTAC is more conductive presenting electric conductivity at low frequencies around 6.0 × 10−4 S cm−1, whereas in the films with the clay PALY-CTAB conductivity reaches 1.4 × 10−6 S cm−1, that is approximately four times smaller. It was observed that films with clay and those that are doped become much more conductive than the electrical blend of PANI/PVA doped as well.