Determination of the exchange enthalpy and entropy parameters of the equation-of-state theory for poly(dimethyl siloxane) in various solvents

Abstract

The interaction parameter chi(t)(infinity) and the effective exchange energy parameter (X) over bar(12) at infinite dilution of cyclohexane, benzene and chlorobenzene with poly(dimethyl siloxane) were determined around room temperature, according to relations given in the Flory formulation of the equation-of-state theory using the inverse gas chromatography technique. Then. the exchange enthalpy X(12) and entropy Q(12) parameters were determined by using a relation for the enthalpy interaction parameter chi(h) of the equation-of-state theory, which is arranged for the inverse gas chromatography conditions. The values of the above-mentioned parameters are comparable with the values obtained earlier with other methods. The X(12) and Q(12) parameters of cyclohexane increase slightly with temperature, while those of benzene and chlorobenzene are almost independent of temperature. Copyright (C) 1996 Elsevier Science Ltd.