Variation of Current-Density as a Function of Electric-Field Intensity in Synthetic Nanoclay-filled Polypropylene

Within the scope of this study variation of current-density with electric-field intensity is studied in polypropylene filled with 0% (plain polypropylene), 2%, 4% and 8% synthetic nano-clay by weight. While recording the rms voltage and current, the power-frequency voltage (60Hz) was raised across each specimen at a speed of 226 V/s. In order to see the reproducibility of the results, 5 samples, with the same nano-clay concentration, were subjected tests under the same conditions. Each specimen under test revealed that the current-density varied non-linearly with the electric-field intensity. Moreover, some degree of saturation was observed at relatively higher electric fields in all the specimens. The saturation of the synthetic-clay loaded nanocomposite started at higher electric fields than the plain polypropylene. Up to a critical electric field intensity the capacitance of the materials was found to be almost constant, but for the electric fields higher than the critical electric field, the material behaves non-linearly leading to a dramatic reduction in capacitance.