Relaxation response of polymers containing highly flexible side groups monitored by broadband dielectric spectroscopy

Abstract

The relaxation behavior of poly(5-acryloxymethyl-5-methyl-1,3-dioxacyclohexane), a polymer containing highly flexible side groups, is studied by broadband dielectric spectroscopy in the frequency and temperature ranges 10–1–109 Hz and 123–473 K, respectively. Above the glass transition temperature Tg the dielectric loss in the frequency domain exhibits a prominent absorption, followed in increasing order of frequencies by two secondary absorptions called and . At temperatures slightly higher than Tg, the relaxation is well separated from the , but as temperature increases overlapping between both relaxations augments forming an absorption in the vicinity of 420 K. This latter absorption displays a shoulder on its high-frequency side corresponding to the relaxation. The strength of the relaxation decreases with increasing temperature, eventually vanishing at the temperature at which the absorption is formed. The time retardation spectra of the isotherms are calculated and further used to facilitate the deconvolution of the overlapping relaxations. The fact that the temperature dependence of the relaxation also describes that of the absorption suggests that both relaxations have the same nature. It seems that as temperature increases, the relaxation feeds on the absorption until its complete disappearance. The relaxation, in turn, seems to increase at the expense of the process at high temperature.