Effect of Nanorod Zinc Oxide on Electrical and Optical Properties of Starch-based Polymer Nanocomposites

Sago starch (SS) based polymer nanocomposites (PNCs) were produced with presence of inorganic nanofiller (zinc oxide nanorods). The percentage of zinc oxide nanorods (ZnO-N) was varied from zero to 10 wt% with increment of 2%. Dielectric and conductivity behaviour of SS/ZnO-N polymer nanocomposites were characterised using LCR-frequency analyser. Structural and composition of ZnO-N filler and PNCs were characterised using field emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and Fourier-transform infrared (FTIR) spectroscopy. By increasing the amount of ZnO-N filler in PNCs, a huge difference in properties was observed especially on relative dielectric constant and electrical conductivity. As the ZnO-N filler content was increased to 10% of total solid, the electrical conductivity and relative dielectric constant of PNCs were observed to increase by 53% (to 0.95 μS cm^–1) and 60% (to 44.1), respectively. The tangent loss in PNCs without filler was measured to be 78% larger (at 7.3) than that of BNC film (at 1.6) with 10% filler content. The highest obtainable room temperature conductivity was 0.95 × 10^–6 S cm^–1 for sample with 10 wt% ZnO-N filler. FESEM micrographs showed no particles agglomeration of ZnO-N in all film samples indicating a uniform distribution of nanoparticles inside the polymer films. Ultraviolet (UV) absorbance shows total absorption of light below 380 nm in all film samples except control film. PNCs with ZnO-N also show zero light transmission below 380nm. FTIR analysis revealed that there was no presence of new functional groups after the application of ZnO-N into PNCs samples indicating that the interaction between ZnO-N and SS polymer was physical in nature.