Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - WoS: 13
    Citation - Scopus: 15
    Determination of Thermodynamic and Transport Properties of Solvents and Non Solvents in Poly(l-Lactide
    (John Wiley and Sons Inc., 2006) Eser, Hülya; Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Thermodynamic properties, partition coefficient, and diffusion coefficients of the various solvents (acetone, dichloromethane, trichloromethane, ethyl acetate, ethyl alcohol, tetrahydrofuran, and water) in poly(lactide-co- glycolide) (PLGA) at infinite dilution of the solvent have been determined by inverse gas chromatography (IGC). In IGC method, which is based on the characteristic equilibrium partitioning of a solute between a mobile phase and a stationary phase, a small pulse of solvent is introduced into the column and by the aid of retention volume of the solvent, several polymer solvent interaction properties, namely retention volume (Vg), infinitely dilute weight fraction activity coefficient (Ω1∞), Flory-Huggins interaction parameter (χ), and solubility parameters of the polymer (δ2∞) can be determined. The thermodynamic results indi cated that trichloromethane and dichloromethane were the most suitable solvents among all the solvents studied for PLGA. The partition (K) and diffusion coefficients (Dp) of various solvents at infinite dilution of the solvent were calculated by using the model developed by Pawlisch et al. (Macromolecules 1987, 20, 1564). The optimum K and D p values that best fit the data were found and the model predicted experimental data very well. So IGC method is a powerful tool for the determination of thermodynamic and diffusion properties of solvent in polymer at infinite dilution of the solvent.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 28
    Influence of Swelling and Diffusion-Induced Convection on Polymer Sorption Processes
    (John Wiley and Sons Inc., 2002) Alsoy Altınkaya, Sacide; Alsoy Altınkaya, Sacide; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Unsteady-state sorption of a vapor or liquid by a polymer is modeled to include the influence of the moving phase boundary associated with the polymer swelling and diffusion-induced convection. A formulation presented clearly elucidates the influence of these two effects on the overall sorption process. Numerical solutions of the model equations indicate the errors that can be induced when swelling or convection are neglected. For most polymer-solvent systems, the influence of the diffusion-induced convection associated with volume changes in mixing can be neglected in the analysis of sorption processes. In contrast, the correction for the moving boundary or swelling of the polymer phase can be quite significant, particularly when a large step change in solvent concentration is considered.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 18
    Solvent Diffusion in Amorphous Polymers: Polystyrene-Solvent Systems
    (John Wiley and Sons Inc., 2000) Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The inverse gas chromatography (IGC) technique was used to obtain the partition and diffusion coefficients of solvents in polystyrene over a wide range of temperatures. Infinite dilution experiments were performed with three solvents: toluene, benzene, and hexane. Finite concentration data were measured for the polystyrene-toluene system at various concentrations from 110 to 180 °C. For the finite concentration region, the modified capillary column model used by Tihminlioglu and Danner (J Chromatogr A 1999, 845, 93-101) was used to calculate diffusion and thermodynamic data. Finite concentration thermodynamic data were also calculated with the retention theory approach and compared with the capillary column model. The experimental IGC results are in good agreement with data from other experimental techniques.