Space Charge Characteristics and Electrode Effect in Linear Low-Density Polyethylene

Abstract

The effects of temperature and electrode materials on space charge distributions of Linear Low-Density Polyethylene (LLDPE) polymerized with Ziegler catalyst were measured with the pulsed electro-acoustic (PEA) method. The thickness of a sample was about 100 µm. Positive space charge was dominant and it changed from homo to hetero space charge with temperature. The mobility of positive charge was 8.1×10-15 m2V-1s-1 at 23°C and 1.0×10-14 m2V-1s-1 at 30°C. On the other hand, the mobility of negative charge was 3.7×10-15 m2V-1s-1 at 30°C. The positive space charge accumulating near the cathode enhanced the electron injection and, as a result, the charging current. The electrode materials used were aluminum and semi-conductive polymer. The space charge distribution and the charge injection depended on electrode conditions. © 2003, The Institute of Electrical Engineers of Japan. All rights reserved.