ELECTRICAL-CONDUCTION IN BIAXIALLY-ORIENTED POLYPROPYLENE

The electrical conduction in biaxially-oriented polypropylene (BOPP) has been studied. Space charge limited current (SCLC), Schottky and Poole-Frenkel effects and ionic conduction processes are discussed. Thermally stimulated polarization current (TSPC) studies showed a decrease in conductivity from 4.3 x 10(-16) to 3.0 X 10(-17) (ohm cm)-1 at 80-degrees-C after hexane treatment of BOPP. The decrease can be attributed to the removal of impurities by hexane treatment. The conduction is extrinsic in nature. Thermally stimulated current investigations show the presence of impurity traps in BOPP. A good fit of the ionic theory to be experimental data of the steady state currents in the temperature range 50-100-degrees-C suggests ion conduction to be predominant. Bulk electronic conduction also plays important role at high temperatures.