Decay of Electrical Charges on Polyethylene Terephthalate Surface

Abstract

Surface potential decay (SPD) characteristics of a corona charged polyethylene terephtalate (PET) are investigated experimentally. A negative corona discharge produced in a needle – grid – plate electrode system was employed to charge the surface of the film samples (thickness: 0.5 mm; surface: 50 mm x 50 mm). The temperature effect, initial potential and relative humidity are presented. The variation domains for the three factors were respectively: 20 to 60°C; -1000 to -1800 V; 20 to 80%. All surface potential decay measurements were carried out in a commercial climatic chamber, where relative humidity RH and temperature T were rigorously controlled. The aim of the present work is to demonstrate the effectiveness of the Experimental methodology for evaluating the effects of these factors. This investigation has showed that the surface potential decay is highly conditioned by temperature, relative humidity and charge density initially lay down on the material. Charge injection mechanism in material bulk seems to be the more probable hypothesis to explain charge flow in PET. More over, the experiment results confirm the influence and the role of thermal activation and electrical field on the potential decay .