COMPARATIVE-STUDY OF THE RELAXATION BEHAVIOR AT VERY-LOW FREQUENCIES OF ACRYLATE POLYMERS WITH PENDANT 1,3-DIOXANE RINGS IN THEIR STRUCTURE

The dielectric activity of poly -[(acryloxy)methyl]-5-methyl-1,3-dioxa cyclohexane} (PAMMD), 5-[(acryloxy)methyl]-5-ethyl-1,3-dioxacyclohexan e} (PAMED) and poly{5-[(acryloxy) methyl]-2-phenyl-5-ethyl-1,3-dioxacy clohexane} (PAEDP) is studied by thermostimulated discharge current (T SDC) techniques. The global TSDC curves corresponding to PAMMD, PAMED, and PAEDP exhibit subglass absorptions centered in the vicinity of -1 05, -100, and -120 degrees C, respectively. The dielectric activity of PAEDP in the glassy region is negligible in comparison with that of b oth PAMMD and PAEDP which have nearly similar relaxation strengths. Pr ominent peaks associated with the glass-rubber transition are located at 41, 38, and 57 degrees C for PAMMD, PAMED, and PAEDP, respectively. The real and loss components of the complex dielectric permittivity i n the frequency domain (10(-10)-10(-2) Hz) were calculated at several temperatures from elementary peaks obtained by partial TSDC curves in the glassy region. The differences observed in the spectra are discuss ed in terms of previous molecular dynamics studies carried out in mode l compounds of the flexible side groups of these polymers. (C) 1998 Am erican Institute of Physics. [S0021-8979(98)08419-9].