Biyoinformatik ve Genetik Bölümü Koleksiyonu

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Browsing Biyoinformatik ve Genetik Bölümü Koleksiyonu by Journal "Advances in Polymer Technology"

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    Citation - WoS: 15
    Citation - Scopus: 15
    A Fluorescence Study on Swelling of Hydrogels (paam) at Various Cross-Linker Contents
    (Wiley, 2009) Aktas, Demet Kaya; Evingür, Gülşen Akin; Pekcan, Önder; Molecular Biology and Genetics; 05. Faculty of Engineering and Natural Sciences; 01. Kadir Has University
    Disk-shaped acrylamide (AAm) gels were prepared from AAm with various NN'-methylenebisacrylamide (Bis) contents as cross-linker in the presence of ammonium persulfate as an initiator by free-radical cross-linking copolymerization in water. Polyacrylamide (PAAm) gels were dried before using for swelling experiments. Steady-state fluorescence spectrometer was employed during the swelling of PAAm hydrogels in water. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine from various Bis content gel samples was measured during in situ swelling process. It was observed that fluorescence intensity decreased as swelling has proceeded. Gravimetric and volumetric experiments were also performed. The Li-Tanaka equation was used to determine the swelling time constants tau(c) and cooperative diffusion coefficients D-c from intensity weight and volume variations during the swelling processes. It was observed that swelling time constants tau(c) increased and diffusion coefficients D-c decreased as the cross-linker content was increased. (C) 2010 Wiley Periodicals Inc. Adv Polym Techn 28:215-223 2009
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    Citation - WoS: 1
    Citation - Scopus: 1
    Investigation of Drying of Poly(n-Isoproplacrylamide by Fluorescence Technique
    (Wiley-Blackwell, 2013) Evingür, Gülşen Akin; Pekcan, Önder; Molecular Biology and Genetics; 05. Faculty of Engineering and Natural Sciences; 01. Kadir Has University
    The steady-state fluorescence technique was performed on drying of various molar percentages of poly(N-isopropylacrylamide-co- acrylamide) [poly(NIPA-co-AAc)] to elucidate the mechanism of temperature-induced phase separation and the effect of monomer content. Poly(NIPA-co-AAc) copolymers were prepared by free radical cross-linking copolymerization. The fluorescence intensity I of pyranine introduced as a probe increased as drying time was increased for all samples. The behavior of I was modeled by using the SternVolmer equation combined with the moving boundary diffusion model. The desorption coefficient D increased as NIPA content was increased at a given temperature. Gravimetric and volumetric experiments also supported the results of the fluorescence technique. The energy E values were measured for the drying processes for each molar percentage of NIPA monomer content by using fluorescence gravimetric and volumetric methods respectively. It is understood that E values decrease by increasing NIPA content until 50% NIPA and then increase after 50% NIPA indicating that the phase separation has occurred at 50% NIPA. (c) 2012 Wiley Periodicals Inc. Adv Polym Techn 32: E231E240 2013