ROLE OF MOLYBDENUM TRIOXIDE ON THERMAL STABILITY OF POLYANILINE NANOCOMPOSITE

Abstract

Molybdenum trioxide (MoO3) grains were coated with conducting organic polymer of polyaniline. The as-prepared nanocomposite samples were characterized by Fourier transformed infrared (FTIR) spectra, X-ray diffraction (XRD) and Thermogravimetry (TGA). The XRD curves shows that, [Formula: see text] have high crystallinity due to the presence of large number of sharp peaks. From the XRD pattern the particle size is evaluated by using Debye-Scherrer's formula and the average particle size of [Formula: see text] and [Formula: see text] nanocomposites are found to be 46 and 32 nm, respectively. This is clearly observed that the condensed particle size of nanocomposite materials is due to the insertion of metal oxide of molybdenum. The incorporation of metal oxide of MoO3 in polyaniline (Pani) is confirmed by FTIR spectral studies. After de-doping, the characteristic peaks of Pani for all the Pani materials are almost same. This is due to the leaching of metal oxide of MoO3 from Pani. From these observations it is noted that doping–dedoping can also take place in inorganic metal oxides. The thermogram showed a three-step degradation process. The first weight loss step was due to the removal of physisorbed water molecules and moisture. The second minor weight loss step was associated with the removal of dopant from Pani backbone and the slight degradation of benzenoid structure of Pani and their thermal stability is enhanced. The third weight loss step was ascribed to the degradation of quinoid form of Pani. This confirmed the thermal stability of [Formula: see text] nanocomposite system. After degradation above 1000°C, the Pani with MoO3 showed a remaining weight of 8%. This confirmed that incorporation of metal oxide in the Pani nanocomposites is 8%. The enhancement of thermal stability is due to the intercalation of Pani chains into MoO3 in first two step degradation, which is further supported by FTIR and XRD reports. The third step degradation of Pani with MoO3 nanocomposite is loosely bound in organic and inorganic part. Therefore, the organic part is easily decomposed.