Temperature-dependent AC electrical conductivity, thermal stability and different DC conductivity modelling of novel poly(vinyl cinnamate)/zinc oxide nanocomposites

Abstract

Novel nanocomposites based on poly(vinyl cinnamate) (PVCin)/zinc oxide (ZnO) were prepared by in situ polymerization method using different mass percentages of ZnO nanoparticles. The formation of nanoparticles in the composites was analysed by TEM, FESEM, XRD, DSC and TG measurements. The TEM and SEM images showed the uniform dispersion of nanoparticles within PVCin matrix. The results of XRD indicated that the metal oxide particles had entered into macromolecular chain of PVCin. The glass transition temperature of the composites was shifted towards higher temperature with the increase in concentration of ZnO nanoparticles. Thermal stability studies showed a remarkable increase in thermal resistance of composites, and the thermal stability increases with an increase in concentration of metal oxide particles. The alternate current (AC) electrical conductivity of prepared composite has been investigated at different temperature at various frequencies. The electrical conductivity was found to be increased with increasing temperature, and it obeys power law. The activation energy was determined from the AC conductivity. DC conductivity of all the composites was much higher than pure PVCin, and the conductivity increases with increase in the concentration of nanoparticles up to 7 mass% and thereafter the conductivity decreases with further addition particles. The experimental conductivity of nanocomposite was compared with different theoretical conductivity using Scarbrick, Bueche and McCullough equation. The conductivity values obtained from McCullough model showed the same trend as experimentally determined conductivity values.