Chemical Engineering / Kimya Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/14

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Author: search.filters.author.Zielinski, John M.Scopus Q: search.filters.scopusQuartile.N/A

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  • Article
    Citation - WoS: 6
    Citation - Scopus: 7
    Solubility and Diffusivity of Methylmethacrylate and Butylacrylate Monomers in a Mma-Ba Copolymer
    (John Wiley and Sons Inc., 2007) Yürekli, Yılmaz; Alsoy Altınkaya, Sacide; Zielinski, John M.
    Mutual diffusion coefficients and sorption isotherms of methyl methacrylate (MMA) and butyl acrylate (BA) monomers in methyl methacrylate-butyl acrylate copolymer (MMA-BA) have been measured by gravimetric sorption. MMA is found to have higher solubility and diffusion rates in the copolymer than BA. Sorption data for MMA were interpreted using classical Flory-Huggins thermodynamic theory with a constant interaction parameter (χ). A modified version of this theory has been applied to correlate the sorption data of BA, which exhibit a temperature and concentration-dependent χ parameter. For MMA, the isotherm data reveal enhanced polymer-solvent interactions with increasing temperature, while for BA the data indicate a drive toward phase separation with increasing temperature. Despite the difference in thermodynamic behavior, both monomers are found to exhibit Fickian diffusion and the diffusivity data are correlated reasonably well with the Vrentas-Duda free volume theory. Some deviation between the free-volume correlation and the experimental data is observed at the lowest temperature and BA concentration examined.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 22
    Onsager consistency checks for multicomponent diffusion models
    (John Wiley and Sons Inc., 2001) Zielinski, John M.; Alsoy Altınkaya, Sacide
    The Onsager reciprocity relations are applied to several recently proposed multicomponent diffusion models in an attempt to gauge their validity and ascertain their applicability. Each of these friction-based diffusion models stems from the more general Bearman formalism through various assumptions regarding the individual friction coefficients. By assessing the compliance of the Bearman model with respect to the Onsager relations, we ascertain the validity of the simplifications introduced to each diffusion model and suggest which postulates lead to results consistent with the Onsager relations. Although some models are not consistent with the Onsager relations, each model predicts the multicomponent drying of polymer films reasonably well. The necessity for consistency with the Onsager development is, therefore, revisited.