MEASUREMENT OF SOLUTE DIFFUSION IN POLYMERS BY INVERSE GAS-CHROMATOGRAPHY USING FUSED-SILICA OPEN-TUBULAR COLUMNS

Inverse gas chromatography (i.g.c.) using a fused-silica open tubular column has been developed and evaluated for measuring diffusion coefficients of small molecules in polymers; this diffusivity data can be used, for example, to model reactive extrusion processes. We have shown the applicability of this technique by measuring the diffusion and partition coefficients of various small molecules in polystyrene, poly(methyl methacrylate) (PMMA), and poly(methyl methacrylimide). The results for polystyrene and PMMA were in good agreement with existing data by gravimetric sorption/desorption, packed column and glass capillary column i.g.c. techniques. The diffusion data for the polyimide were generated for the first time.