Thermodynamics of poly(benzyl methacrylate)–probe interactions at different temperatures by using inverse gas chromatography

• Thermodynamic properties of poly(benzyl methacrylate) were studied by inverse gas chromatography.
• Polymer–solute interactions of poly(benzyl methacrylate) were studied by inverse gas chromatography.
• The solubility parameter of polymer was calculated from inverse gas chromatography.

In this study, some thermodynamic properties of poly(benzyl methacrylate) (PBzMA) were studied by using the inverse gas chromatography (IGC) technique. The retention times (tr) of probes were determined from the interactions with PBzMA of four groups of solvents with different chemical natures and polarities. Then, specific volume (Vg0) values were determined for each probe molecules. The glass transition temperature (Tg) of PBzMA was found as 323 K from inverse gas chromatography measurements. Under the glass transition temperatures adsorption heat (ΔHa) and above the glass transition molar heat (ΔH1S), free energies (ΔG1S) and entropies (ΔS1S) belonging to sorption for every probe were calculated from inverse gas chromatography measurements. The partial molar heat (ΔH1∞), partial molar free energy (ΔG1∞), Flory–Huggins interaction parameter (χ12∞) and weight fraction activity coefficient (a1/w1)∞, values for infinite dilute solutions were calculated for polymer–probe systems. The solubility parameter (δ2) of the polymer was obtained from the slope and intercepts of Flory–Huggins interaction parameter (χ12∞) graphs with solubility parameters (δ1) of probes.

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