Optical, thermal and temperature dependent electrical properties of chlorinated natural rubber/copper alumina nanocomposites for flexible electrochemical devices

The present investigation focuses on the optical, thermal, temperature-dependent alternating current (AC) and activation energy of chlorinated natural rubber (Cl-NR)/ copper alumina (Cu-Al2O3) nanocomposite systems. Temperature-dependent dielectric properties like dielectric permittivity, modulus and complex impedance were analyzed in the frequency region of 10(2) to 10(6) Hz. The effect of Cu-Al2O3 on the DC conductivities was correlated with various theoretical approaches like Scarisbrick, McCullough and Buche model. The surface behaviour of chlorinated NR with Cu-Al2O3 composites was analysed by contact angle measurements. The composite with 5 phr Cu-Al2O3 incorporated Cl-NR showed the least bandgap energy and maximum absorbance in the UV spectra. The TGA shows the thermal decomposition temperature of the rubber nanocomposite with an increase in the concentration of nanoparticles. The non-perfect linear plots obtained from AC conductivity showed the non-ohmic type of conduction in composite systems. The semiconducting nature was illustrated by the semi-circular Cole-Cole plot observed for Cl-NR/ Cu-Al2O3 composites. The lowest dielectric modulus was observed for the composite with 5 phr sample indicated the electron hopping conduction. Theoretical conductivity obtained from McCullough model was found to be best to explain the experimental DC conductivity. According to the results of this study, the Cl-NR/ Cu-Al2O3 nanocomposites can be a paramount alternative in the fabrication of important flexible dielectric materials like actuators, sensors, electromagnetic interference shielding and super-capacitors.