Mobility of Small Molecules in Polymer Systems

Abstract

AbstractSeveral theoretical correlations between glass temperature depression and concentration of plasticizer, known from literature, were examined on their use in describing self‐diffusion processes with the non‐linear extension of the Fujita theory [1 ‐3, 8]. — The experiments involved measurements of the self‐diffusion in various polymer‐solvent systems with the spin‐echo technique as well as glass temperature measurements conducted on a differential scanning calorimeter. ‐ The results show that both the theories of Kanig [13–15] and Kilian [16, 17] and especially the theory of Mandelkern [18] can be successfully used in describing the experimentally observed glass temperature and self‐diffusion dependence. ‐ The calculated free volume shows a non‐linear dependence in the range of high polymer concentrations.—The self‐diffusion behaviour could be correlated to the free volume by a nearly temperature‐independent relationship.