DIFFUSION OF SOLVENTS IN POLYBUTADIENE RUBBER USING CAPILLARY COLUMN INVERSE GAS-CHROMATOGRAPHY

The capillary column inverse gas chromatography (CCIGC) method at infi nite dilution of solvent was used to measure the diffusion and partiti on coefficients of cyclohexane, toluene, n-heptane, chloroform and met hyl ethyl ketone in polybutadiene (BR, 95% cis). Experiments were perf ormed over a temperature range of 0 to 70 degrees C. Chromatographic d ata analysis was carried out in terms of the elution model described b y Pawlisch and coworkers.(1,2) Attempts to conduct experiments at temp eratures below 0 degrees C yielded erroneous results. At these low tem peratures the high activity of the solvent causes the system to be far from the linear portion of the absorption isotherm or in some cases r esults in condensation in the capillary column. The Vrentas-Duda free- volume diffusion model was used to interpret and correlate the diffusi on data obtained at infinite dilution of the solvent.