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    Determination of thermodynamic properties of poly (cyclohexyl methacrylate) by inverse gas chromatography
    (Zhongguo Kexueyuan - Chinese Academy of Sciences, 2014) Kaya, İsmet; Yiğit Pala, Çiğdem
    In this work, some thermodynamic properties of poly (cyclohexyl methacrylate) were studied by inverse gas chromatography (IGC). For this purpose, the polymeric substance was coated on Chromosorb W and which was filled into a glass column. The retention times (tr) of the probes were determined from the interactions of poly ( cyclohexyl methacrylate) with n-pentane, n-hexane, n-heptane, n-octane, n-decane, methanol, ethanol, 2-propanol, butanol, acetone, ethyl methyl ketone, benzene, toluene and o-xylene by IGC technique. Then, the specific volume (V0g) was determined for each probe molecule. By using (1 /T; lnV0g) graphics, the glass transition temperature of poly(cyclohexyl methacrylate) was found to be 373 K. The adsorption heat under the glass transition temperature (?Ha), and partial molar heat of sorption above the glass transition (?Hs1)' partial molar free energy of sorption (?Gs1) and partial molar entropy of sorption (?Ss1) belonging to sorption for every probe were calculated. The partial molar heat of mixing at infinite dilution (?H?1), partial molar free energy of mixing at infinite dilution (?D?1), Flory-Huggins interaction parameter (??12) and weight fraction activity coefficient (a1/w1)? values of polymer-solute systems were calculated at different column temperatures. The solubility parameters (?2) of the polymer were obtained by IGC technique.
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    Thermodynamics of poly(benzyl methacrylate)-probe interactions at different temperatures by using inverse gas chromatography
    (Elsevier Science Bv, 2014) Kaya, İsmet; Yiğit Pala, Çiğdem
    In this study, some thermodynamic properties of poly(benzyl methacrylate) (PBzMA) were studied by using the inverse gas chromatography (IGC) technique. The retention times (t(r)) of probes were determined from the interactions with PBzMA of four groups of solvents with different chemical natures and polarities. Then, specific volume (V-g(0)) values were determined for each probe molecules. The glass transition temperature (T-g) of PBzMA was found as 323 K from inverse gas chromatography measurements. Under the glass transition temperatures adsorption heat (Delta H-a) and above the glass transition molar heat (Delta H-1(S)), free energies (Delta G(1)(S)) and entropies (Delta S-1(S)) belonging to sorption for every probe were calculated from inverse gas chromatography measurements. The partial molar heat (Delta H-1(infinity)), partial molar free energy (Delta G(1)(infinity)) Flory Huggins interaction parameter (chi(infinity)(12)) and weight fraction activity coefficient (a(1)/w(1))(infinity), values for infinite dilute solutions were calculated for polymer probe systems. The solubility parameter (delta(2)) of the polymer was obtained from the slope and intercepts of Flory Huggins interaction parameter (chi(infinity)(12)) graphs with solubility parameters (delta(1)) of probes. (C) 2014 Elsevier B.V. All rights reserved.