INFLUENCE OF THE MOLECULAR-STRUCTURE ON THE DYNAMICS IN POLY(ESTER-IMIDE)S

Dielectric spectroscopy in the frequency range from 0.1 to 10(5) Hz wa s employed to study the molecular dynamics of main-chain poly(ester-im ide)s (PEIMs) with varying spacer lengths from 5 to 12 methylene units . For all samples three relaxation processes were observed. The beta-p rocess shows an Arrhenius-like temperature dependence with activation energies between 50 and 55 kJ/mol. This process is assigned to a local libration of the ester groups. The alpha-process shows a WFL-like te mperature dependence. It is assigned to a main-chain-coupled motion of the mesogens around their short molecular axes. The alpha-process als o follows a WFL-like temperature dependence. It is assigned to coopera tive main-chain motion of PEIM and it is correlated to the glass trans ition.