By a systematic investigation of solvent polymer systems of even greater complexity, this work analyses the relative performances of UNIQUAC and related models to account for sorption phenomena in polar elastomers (polyurethaneimides) with vapours of moderate to strong polarity (ether, ester, alcohol). Four different UNIQUAC-type models have been chosen for this study : UNIQUAC, UNIQUAC-HB, UNIQUAC-FV and UNIQUAC-FV+HB. They mainly differ in corrective and/or additional terms accounting for particular effects such as free volume (FV) effects or hydrogen bonding (HB) or a combination of both (FV+HB). Their main respective advantages are discussed with regard to the solvent and polymer chemical structures and the type of interactions involved in the sorption phenomenon. UNIQUAC-FV is shown to provide the best results for the sorption of aprotic species (ether, ester) in polyurethaneimides, as could be expected for elastomers for which free volume effects are usually believed to be significant. However, the sorption of a protic species (alcohol) is best described by UNIQUAC-HB, i.e. the UNIQUAC model specifically modified for systems involving strong interactions by hydrogen bonding. Hydrogen bonding could therefore prevail on free volume effects for these particular systems.