Thermodynamics of poly(7-methoxy-2-acetylbenzofurane methyl methacrylate-co-styrene) and poly(2-acetylbenzofurane methyl methacrylate-co-styrene)-probe interactions at different temperatures by inverse gas chromatography

Abstract

In this study, some thermodynamic properties of poly(7-methoxy-2-acetylbenzofurane methyl methacrylate-co-styrene) Poly(MABMM-co-St) and poly(2-acetylbenzofurane methyl methacrylate-co-styrene) Poly(ABMM-co-St) were studied by the inverse gas chromatography (IGC) technique. The retention times (tr) of selected organic probes were determined from the interactions with Poly(MABMM-co-St) and Poly(ABMM-co-St) of four groups of solvents with different chemical natures and polarities. Then, specific volume (Vg0) values of probes were calculated at different column temperatures. The glass transition temperatures (Tg) of Poly(MABMM-co-St) and Poly(ABMM-co-St) were found as 393, 413K from inverse gas chromatography measurements, respectively. 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.