A study of some equation-of-state parameters of poly(methylhydrosiloxane-co-dimethylsiloxane) with some solvents by gas chromatography

Abstract

Trace amount of methyl acetate, ethyl acetate, tert-butyl acetate, pentane, hexane, and heptane were passed through the chromatographic column loaded with poly(methylhydrosiloxane-co-dimethylsiloxane) coated on Chromosorb W. The retention diagrams of the solvents on the copolymer were plotted by means of specific retention volumes at temperatures between 40 and 80 degrees C by inverse gas chromatography technique. In this study, some thermodynamic interaction parameters such as Flory Huggins polymer-solvent interaction parameter, equation-of-state polymer-solvent interaction parameter, effective exchange energy parameter, and weight fraction activity coefficients at infinite dilution of the solvent were determined. Then, the exchange enthalpy parameter and entropy parameter were determined by using a relation for the enthalpy interaction parameter of the equation-of-state theory, which is arranged for the inverse gas chromatography conditions. Later, the partial molar heat of sorption and the partial molar heat of mixing were obtained. The solubility parameter of this copolymer was determined as 6.64 (cal/cm(3))(1/2) at room temperature. (c) 2007 Wiley Periodicals, Inc.