Morphology-Related Packetlike Space-Charge Behavior in Linear Low-Density Polyethylene Doped with Al_2O_3 Nanoparticles

摘要

Packetlike space-charge behavior and the isothermal decay processes of the injected charge in neat linear low-density polyethylene (LLDPE) and LLDPE doped with Al_2O_3 nanoparticles were investigated by the pressure wave propagation method. The 1-mm sheet samples, sandwiched by semiconductive electrodes, were submitted to 40 kV/mm of direct current field at various temperatures for 3 h. The charge-injecting rate and the apparent mobility of packetlike space charge under directcurrent stress were compared among the samples subjected to different blending processes with or without nanoparticles. The slight doping concentration showed a significant influence on the space-charge dynamics, with a lower injecting rate and apparent mobility for higher doped samples. The isothermal decay processes of the injected charge indicated trap-modulated features. The phenomena were considered to be related to the changing morphology of the matrix material.