DETERMINATION OF INFINITE DILUTION DIFFUSION AND ACTIVITY-COEFFICIENTS OF SOLVENTS IN POLYSTYRENE BY INVERSE GAS-CHROMATOGRAPHY ON A CAPILLARY COLUMN

Infinite dilution activity and diffusion coefficients of several solve nts in polystyrene have been measured by inverse gas chromatography on a capillary column for temperatures between 110 and 170-degrees-C. Ch romatographic data have been treated according to Khan's model, evalua ting the contribution to the peak broadening due to radial and axial m olecular diffusion in the mobile phase, radial diffusion in the statio nary phase, and interfacial mass transfer resistance. Four capillary c olumns have been prepared with coating thickness ranging from 0.5 to 3 .3 microns in order to determine the minimum thickness necessary to ob tain reliable measurements of the diffusion coefficient of the solvent in the polymer in every possible experimental condition. Our experime ntal data are in considerable agreement with the data already availabl e in the literature, obtained by static and chromatographic methods. ( C) 1994 John Wiley & Sons, Inc.