Free‐volume interpretations of self‐diffusion in ternary solutions: n‐Paraffin‐hexafluorobenzene‐cis‐4‐polybutadiene

Self‐diffusion of both diluents in the systems n‐paraffin + hexafluorobenzene + cis‐4‐polybutadiene (paraffin = dodecane or hexatriacontane) has been measured at 80°C as function of both concentrations, using field‐gradient spin‐echo techniques (1H and 19F NMR). The data follow the free‐volume model in the form of the Fujita‐Doolittle equation, or the Vrentas‐Duda theory, extended to apply to ternary systems. It is found that the polymer molecular jumping segments are roughly equal in size to the diluent molecules or their jumping segments.