Polymer nanocomposites with good optical, crystalline, morphological, thermal, dielectric, and electrical properties were synthesized using poly(diphenylamine) (PDPA) and zinc oxide (ZnO) nanoparticles. The redshift in the UV absorption edges of composites indicates that ZnO nanoparticles have been successfully incorporated into the PDPA matrix. The lowest optical bandgap energy and maximum refractive indices were observed in 7 wt% loadings. The narrowing of the avearge chain spacing detected by X-ray diffraction (XRD) proved that ZnO had an impact on the structure of PDPA. Scanning electron microscopy (SEM) images show homogeneous dispersion of spherically shaped ZnO nanoparticles at lower filler loadings. The glass transition temperature of the nanocomposites was greatly enhanced with the addition of nanoparticles analyzed by differential scanning calorimetry. The electrical and dielectric properties improved with temperature and nanoparticle loadings up to 7 wt%. The analysis of impedance spectra and the decreasing radius of semi-circular arcs in the Nyquist plot manifests the existence of temperature-dependent conductivity and relaxation phenomenon. The experimental values of DC conductivities were correlated with different theoretical conductivity models and the McCullough model was found to be the most promising one to explain the increased DC conductivity of the PDPA/ZnO nanocomposites.

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Copper alumina (Cu-Al2O3) reinforced poly(aniline- co-indole) (PANI- co-PIN) nanocomposites were prepared and characterised by UV-vis spectroscopy, FE-SEM and DSC. The bandgap energy decreased with the addition of Cu-Al2O3 to PANI- co-PIN. The FE-SEM confirms the uniform dispersion of nanoparticles in the copolymer. The DSC showed a shift in glass transition temperatures to higher regions with Cu-Al2O3 concentrations. The frequency-temperature-dependent dielectric parameters and electrical conductivity of nanocomposites were investigated. Activation energy calculated from Arrhenius equation decreases with increasing frequency. The real and imaginary part of electric modulus implies the thermally activated dielectric relaxations. The decreasing radius of semicircles in Nyquist plot with increasing temperatures indicates the existence of thermally activated conduction mechanisms. Different theoretical models were used to predict the DC conductivity mechanism in copolymer nanocomposites.

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