Zur theoretischen deutung der temperaturabhängigkeit der relaxationszeiten von polymeren

The free volume theory of Cohen and Turnbull, the results of which are identical with the empirical relationship of Williams, Landel and Ferry (WLF), was compared with the theory of conformational entropy of Adam and Gibbs (AG) using experimental results of measurements of the temperature dependence of the relaxation times of poly(vinyl acetate). In spite of being different in their mathematical form, both theories were found to describe the experiment with similar adequacy. A procedure was also suggested permitting to obtain the AG parameters if the WLF parameters are known. The procedure was applied to 59 compounds, the WLF parameters of which were found in the literature. The results are tabulated.