Determination of thermodynamic interactions of poly composite by inverse gas chromatography at infinite dilution

• Published in: Journal of materials science 2014-07, Vol.49 (14), p.5076
• Main Authors: Nastasovic, Aleksandra B, Ignjatovic, Nenad L, Uskokovic, Dragan P, Markovic, Dana D, Ekmescic, Bojana M, Maksin, Danijela D, Onjia, Antonije E
• Format: Article
• Language: English
• Subjects: Analysis; Cyclohexane; Dioxane; Gas chromatography; Phosphates; Thermodynamics
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8214-3

Inverse gas chromatography at infinite dilution was applied to determine the thermodynamic interactions of poly(L-lactide) (PLLA) and the composite of biphasic calcium phosphate and PLLA (BCP/PLLA). The specific retention volumes, [V.sup.0.sub.g], of 11 organic compounds of different chemical nature and polarity (non-polar, donor or acceptor) were determined in the temperature range of 308-378 K for PLLA and 308-398 K for BCP/PLLA. The weight fraction activity coefficients of test sorbates, [Ω.sup.∞.sub.1], and the Flory- Huggins interaction parameters, [χ.sup.∞.sub.12], were estimated and discussed in terms of interactions of the sorbates with PLLA and BCP/PLLA. Also, the partial molar free energy, Δ[G.sup.∞.sub.1], the partial molar heat of mixing, Δ[H.sup.∞.sub.1], the sorption molar free energy, Δ[G.sup.S.sub.1], the sorption enthalpy, Δ[H.sup.S.sub.1], and the sorption entropy, Δ[S.sup.S.sub.1], were analyzed. A different chromatographic behavior of the two investigated samples, PLLA and BCP/ PLLA, was observed. The values of [Ω.sup.∞.sub.1] indicated n-alkanes, diethyl ether, tetrahydrofurane (THF), cyclohexane, benzene, dioxane (except for 338 K), and ethyl acetate (EtAc) (except for 338 K) as non-solvents, and chloroform (CH[Cl.sub.3]) as good solvent (except for 378 K) for PLLA. For BCP/PLLA, CH[Cl.sub.3], EtAc (for 378 K), dioxane (except for 378 K), and THF were indicated as good solvents.