THERMALLY STIMULATED DEPOLARIZATION CURRENT STUDIES ON PC/PTBF BLENDS

Thermally stimulated depolarization current (TSDC) studies have been carried out on blends of polycarbonate (PC) and poly (p-t-butyl phenolformaldehyde) (PTBF) using electric poling at temperatures ranging from 348 degrees K to 383 degrees K. The PC/PTBF blends poled at identical electric field (E(p)) and temperature (T-p) exhibit a continuous distribution of polarizability (in general, in the range 300 degrees K to 450 degrees K) with a blend composition dependent single peak (T-M). With increasing E(P) and T-P, the TSDC peak of a blend shifts toward higher temperature with increasing peak current (I-M) and charge (Q) associated with the peak. The effects of polarization field and temperature indicate that the polarization in the blend system is due to induced dipole formation. The activation energy decreases with increasing PTBF content in the blend, indicating shallow traps in PC/PTBF electret. The present blend electrets, however, comparative to its two components PC and PTBF, store more charge but decay faster. (C) 1994 John Wiley and Sons, Inc.