Broadband dielectric spectroscopy studies of hyperbranched polyglycerols

摘要

The broadband dielectric spectroscopy of three hyperbranched polyglycerols with different molecular weights has been studied. All of the hyperbranched polyglycerols,. exhibited, three relaxation processes, one related to glass transition (a relaxation) and two sub-glass processes (beta and gamma relaxations). The relaxations were analyzed in terms of the Havriliak-Negami equation. The two sub-glass processes collapse with a relaxation in different scenarios at high temperatures and only a broad and apparently symmetric relaxation peak is observed. Within this temperature range, two clearly different tendencies were observed at the low and high extremes of the temperature range.