Study of relaxations in poly(methyl methacrylate)-magneto electrets by thermally stimulated depolarization current and surface-charge-decay mechanisms

摘要

The effect of the forming temperature and the magnetic field was investigated for the charge retention and stability of poly(methyl methacrylate) (PMMA)-magneto electret (ME) samples with thermally stimulated discharge currents (TSDCs) and a surface-charge-decay mechanism. The measurements were performed on a pristine PMMA sample with a thickness of 20 mm. The comparative studies of charge decay with TSDC indicated a strong resemblance between the results of the two techniques of MEs of PMMA and were characterized by two TSDC peaks, that is, an α peak at 110°C and a P peak at 160°C. The low-temperature peak (i.e., the α peak) was associated with dipolar relaxation, and the high-temperature peak (i.e., the P peak) was attributed to the self-motion of space charges in PMMA.