Relaxation behavior of methacrylic polymers with bulky hydrophilic groups in their structures

The isochrones showing the temperature dependence of the loss relaxation mo dulus of poly(neopentyl glycol methacrylate) present an ostensible subglass absorption called beta relaxation that roughly has the same intensity as t he glass-rubber relaxation, or alpha process. The dielectric relaxation spe ctrum of this polymer also exhibits a well-developed beta process followed at higher temperatures by the glass-rubber, or a relaxation, which strong c onductive effects only permit to be detected at high frequencies. A detaile d study of the conductive contributions to the dielectric loss above T-g wa s carried out using a theory that assumes that the dispersion observed in t an delta in the frequency domain arises from the Maxwell-Wagner-Sillars eff ect combined with Nernst-Planck electrodynamic effects caused by interfacia l polarizations in the interface polymer electrodes. Attempts were made to evaluate the equivalent salt concentration that would produce the conductiv e effects experimentally observed. (C) 1999 John Wiley & Sons, Inc.