DIFFUSION AND EQUILIBRIUM MEASUREMENTS IN TERNARY POLYMER-SOLVENT-SOLVENT SYSTEMS USING INVERSE GAS-CHROMATOGRAPHY

Diffusion and equilibrium coefficients in ternary polymer-solvent-solv ent systems were measured using inverse gas chromatography (IGC). The technique provides a new approach to probe diffusion in ternary polyme r-solvent-solvent systems. The self-diffusion coefficients of a solven t in a mixture of a polymer and a second solvent were measured. Experi ments were performed for the diffusion of toluene and methanol in the poly(vinyl acetate) (PVAC)-toluene-methanol system and for diffusion o f toluene and heptane in the polybutadiene (PDB)-toluene-heptane syste m. Predictions of diffusivities in ternary systems based on the free-v olume theory are also critically analyzed and compared with the experi mental data.