Based on the Hadj-Romdhane-Danner mathematical model of the chromatographic process, the infinite dilution diffusion coefficients of cyclohexane in polyethylene (PE) and polyisobutylene (PIB) were measured in the temperature range between 323.2 and 363.2K by reverse gas chromatography. The experimental data show that the diffusion data of cyclohexane in PE are smaller than those in PIB at the same temperature, which indicates that the diffusion of cyclohexane in PE membrane is more difficult if compared with PIB membrane. The correlation of the experimental data was performed by using the modified Vrentas-Duda free-volume equation, where the hole free volume was introduced instead of the whole free volume in the Vrentas- Duda initial equation. The correlated results show that the modified equation is a quite good description of the relationship between the observed diffusion data and the temperature.

Key words: CYCLOHEXANE, POLYETHYLENE, POLYISOBUTYLENE, DIFFUSION COEFFICIENTS, FREE VOLUME, POLYMER FILMS