Diffusion of Solvents in Polybutadiene Rubber Using Capillary Column Inverse Gas Chromatography

The capillary column inverse gas chromatography (CCIGC) method at infinite dilution of solvent was used to measure the diffusion and partition coefficients of cyclohexane, toluene, n-heptane, chloroform and methyl ethyl ketone in polybutadiene (BR, 95% cis). Experiments were performed over a temperature range of 0 to 70°C. Chromatographic data analysis was carried out in terms of the elution model described by Pawlisch and coworkers. Attempts to conduct experiments at temperatures below 0°C yielded erroneous results. At these low temperatures the high activity of the solvent causes the system to be far from the linear portion of the absorption isotherm or in some cases results in condensation in the capillary column. The Vrentas-Duda free-volume diffusion model was used to interpret and correlate the diffusion data obtained at infinite dilution of the solvent.