Electrical and structural investigations of PVA/CMC/PPy/MWCNTs blended polymer composites for energy storage applications

This work aims to form polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)/0.1 wt% polypyrrole (PPy)/x wt.% multi-walled carbon nanotubes (MWCNTs) blended polymers using the casting technique to employ in energy storage applications. X-ray diffraction and scanning electron microscopy are used to investigate the structure and morphology of the formed blends. The maximum values of dielectric constant and energy density were obtained at x = 0.05. The dielectric constants are influenced by both the temperature and the concentration of MWCNTs, as well as the existence of PPy in the blended matrix. Blends with x = 0 and 0.2 displayed the small polaron mechanism, blends with x = 0.05 and 0.25 followed the CBH model, whereas the remaining samples demonstrated the OLP mechanism. Z ' reaches its maximum values at x = 0.2 and its lowest values at x = 0.05 in the low and intermediate frequency regions. In the higher frequency range doped blends have the lowest Z ' values as compared with the undoped blend. Samples with x = 0.05, 0.15, and 0.2 exhibit semiconductor properties, whereas the remaining samples display features associated with either insulators or partial conductors. The effect of MWCNTs doping amount and temperature on the ionic conductivity, electric modulus and relaxation time of different blends was studied. Also, the activation energy of every blend was determined using the Arrhenius relation.