STUDY OF CHARGE STORAGE PROPERTIES IN BIAXIALLY ORIENTED POLYPROPYLENE

The charge storage properties of corona charged biaxially-oriented pol ypropylene (BOPP) and unoriented polypropylene (PP) films have been st udied. Thermally stimulated charge decay and open and short circuit th ermally stimulated currents were measured. A half value charge decay t emperature T0.5 = 118-degrees-C for BOPP was 20-degrees-C higher than for PP, hence giving greater charge storage stability for BOPP. The ch arge storage in BOPP is attributed predominantly to impurity trapping and space charge mechanisms. X-ray and differential scanning calorimet ry methods were employed to obtain structural information.