Study of charge storage properties in biaxially oriented polypropylene

The charge storage properties of corona-charged biaxially oriented polypropylene (BOPP) and unoriented polypropylene (PP) films have been studied. Thermally stimulated charge decay and open and short circuit thermally stimulated currents, were measured. A half-value charge decay temperature for BOPP was T/sub 0.4/=118 degrees C, 20 degrees C higher than for PP, hence giving greater charge storage stability for BOPP. The charge storage in BOPP is attributed predominantly to impurity trapping and space charge mechanisms. X-ray and differential scanning calorimetry methods were employed to obtain structural information.>