Inverse gas chromatography (IGC) has been widely used to determine the FloryHuggins parameters, chi, between solutes (probes) and polymers. In a previous study a multiparameter acidbase model, which included dispersion, polarity, acidity, and basicity components, was used to correlate the Flory-Huggins parameters of a series of probes obtained from IGC measurement. Using IGC data from two polymers the parameters of poly(epsilon-caprolactone) (PCL) and polyepichlorohydrin (PECH) were calculated and used to estimate the interaction parameter between them. In the present study a modified linear method was proposed to obtain the parameter differences between the two polymers directly from their chromatographic retention data. This method offers a more convenient assessment on the mutual miscibility between the two polymers. This method is also related to the linear solvation energy relationship (LESR). Correlations between the descriptors of LESR and the parameters in this acidbase model are discussed. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012