Thermodynamical study of poly( n ‐hexyl methacrylate) with some solvents by inverse gas chromatography

The retention volume diagrams of ethyl acetate, isobutyl acetate, tert ‐butyl acetate, benzene, n ‐hexane, n ‐heptane, n ‐octane, acetone, chloroform, and acetonitrile on the poly( n ‐hexyl methacrylate) (PHMA) were plotted at temperature ranges from 333 to 393 K by inverse gas chromatography technique. Some polymer‐solvent thermodynamic interaction parameters, such as weight fraction activity coefficient, Ω   1 ∞ , Flory‐Huggins, χ   12 ∞ , hard‐core, χ   12 * , and some exchange parameters such as effective energy, X eff , enthalpy, X 12 , and entropy, Q 12 , were determined for studied solvents at infinite dilution of PHMA at temperatures mentioned above. Then the partial molar heat, $\Delta \overline H_1^s$ , and free energy, $\Delta \overline G_1^s$ , of sorption as well as the partial molar heat, $\Delta \overline H_1^\infty$ , and free energy, $\Delta \overline G_1^\infty$ , of mixing at infinite dilution were determined. In addition, the solubility parameter of PHMA, δ 2 , was determined as 8.8 (cal/cm 3 ) 1/2 at room temperature by extrapolation of the values of solubility parameters from studied temperatures to 298 K. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011