Structural, Electrical, Thermal and Transport Properties of Poly Pyrrole/La0.7Ca0.3MnO3 Perovskite Manganite Nano Composite Studies Above Room Temperature

This paper presents the thermal studies of organic-inorganic [Poly Pyrrole (PPy)-Lanthanum calcium manganite (LCM)] nano composites synthesized via facile in situ chemical oxidation and sol gel methods respectively. The morphology and crystal structure were analysed through scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) techniques respectively. The ac electrical conductivity, transport properties like dielectric constant, dielectric loss, real and imaginary part of electric modulus of pure PPy and PPy/LCM nano composites were analyzed in the temperature range 30 degrees C to 180 degrees C and in the frequency range from 100 Hz-5 MHz. Thermal stability of pure PPy and PPy/LCM nano composites were analyzed in the temperature range 30 degrees C to 800 degrees C by Thermogravimetric analysis (TGA) and Differential thermal analysis. The contributor for thermal degradation were analysed by fourier transmission infra red studies. DC conductivity study was carried out in the temperature range 30 degrees C to 180 degrees C. The activation energy was calculated using arrhenius plots. SEM and TEM images show spherical structure for pure PPy, agglomeration for pure LCM and PPy/LCM nano composites show spherical with LCM embedded in the PPy chain. The XRD analysis for pure PPy, LCM and PPy/LCM nano composites show amorphous, orthorhombic and semicrystalline structures respectively. AC electrical conductivity of the samples tend to merge at high frequency side. Dielectric constant show frequency dependence at all temperature. Real and complex electric modulus analysis show contribution of grain and grain boundary for the ac electrical conductivity. DC conductivity shows ionic conduction. The AC and DC conductivities were found to be high for PPy/LCM30 weight percent and PPy/LCM40 weight percent nano composites respectively. The activation energy of PPy/LCM40 was found to be high. TGA shows that the glass transition temperature of pure PPy is not much affected with the incorporation of LCM nano particle to the PPy chain.