Study of Relaxations in Poly(methyl methacrylate)-Magneto Electrets by Thermally Stimulated Depolarization Current and Surface-Charge-Decay Mechanisms

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 alpha peak at 110 degrees C and a rho peak at 160 degrees C. The low-temperature peak (i.e., the alpha peak) was associated with dipolar relaxation, and the high-temperature peak (i.e., the rho peak) was attributed to the self-motion of space charges in PMMA. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 29-34, 2011