Yazar "Dinc, Cemile Ozdemir" seçeneğine göre listele

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    Carrying system formula for eugenol encapsulation: glycodendritic polyamine dextran-G2.5, synthesis and in vitro antibacterial activity
    (Springer, 2021) Bucak, Celile Demirbilek; Kurekci, Cemil; Dinc, Cemile Ozdemir
    A novel 2.5th-generation glycodendritic polyamine dextran with 96 arms (DPADx) was synthesized by the divergent method. 2.5th-generation dendrimer was obtained from the successive triplicate Michael addition with two amidation reactions using 0.5th-generation tris(2-aminoethyl)amine (TAEA-G0.5) as the initiator core. 2.5th-generation polyamine hydrazide (PAH) was obtained from hydrazine monohydrate. Finally, dextran was conjugated with PAH and so DPADx was obtained. FTIR, H-1- and C-13-NMR, elemental analysis, GPC, XRD, SEM, TGA, DSC and dynamic viscosity were used for structural analysis of products. Loading efficiency, capacity and yield (%) of eugenol-encapsulated glycodendrimer were calculated as 70%, 84% and 35%, respectively; by using UV-Vis analysis results, antimicrobial activity against Gram-positive (Staphylococcus aureus, Listeria monocytogenes and Enterococcus cesseliflour) and Gram-negative (Escherichia coli and Salmonella Typhimurium) bacteria was proven. The current study demonstrated the usability of the novel dendritic glycopolymer as an innovative and environmentally friendly way to encapsulate and shuttle of EOs without altering sensory characteristics and the functionality of these molecules. Therefore, its commercial application is possible in a variety of fields, such as pharmaceutic and cosmetic industries.
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    Design, synthesis and characterization of a pH-sensitive DS/GM hydrogel
    (Polymer Soc Korea, 2015) Ozenir, Zeynep; Demirbilek, Celile; Dinc, Cemile Ozdemir
    Dextran sulfate/glycidyl methacrylate (DS/GM) hydrogels were synthesized by intermolecular side-chain reaction of DS hydroxyl groups with monomeric crosslinking agent, GM in aqueous solutions at 75 A degrees C in the basic medium in this study. The optimum conditions of effective crosslinking for DS/GM system were determined with changing amounts of crosslinker and initiator (benzoyl peroxide, BPO). The swelling abilities of the hydrogels were explained with determining of certain structural parameters for the hydrogel such as equilibrium water content, percentages of gellation, and swelling ratio. pH dependent swelling behaviors of hydrogels were investigated and swelling ability at basic medium was higher than that at acidic medium. Surface morphologies of DS and its hydrogels were examined by scanning electron microscope (SEM) and they compared. Structures and thermal stabilities of DS/GM hydrogels were characterized by infrared (FTIR), thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and Differential Scanning Calorimeter (DSC); effect of GM on crosslinking was investigated. The viscosities of DS/GM reaction products were recorded continuously as a function of time with rotary viscometer and gellation points of binary system reaction between DS and GM were determined via observed viscosity numbers, changes during reaction.
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    Diethylaminoethyl dextran/epichlorohydrin (DEAE-D/ECH) hydrogel as adsorbent for murexide
    (Desalination Publ, 2016) Demirbilek, Celile; Dinc, Cemile Ozdemir
    This study describes the dyestuff removal ability of diethylaminoethyl-dextran-epichlorohydrin (DEAE-D-ECH) polymeric adsorbents. The interaction between DEAE-D-ECH hydrogel and a water-soluble dyestuff, murexide (Mu), was investigated. The effect of different parameters on Mu adsorption efficiency was examined in detail. The equilibrium swelling capacity of DEAE-D hydrogel was determined by swelling in water and dye solution. Scanning electron microscopy micrographs and FTIR spectra, before and after the adsorption of Mu on the hydrogel, were used to explain the adsorption. Additionally, kinetic adsorption ability was well described by the pseudo-second-order kinetic model. The equilibrium data were best described by the Langmuir isotherm model. According to the calculated thermodynamic parameters (Delta G degrees, Delta H degrees, and Delta S degrees), the adsorption process is spontaneous and endothermic.
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    Preparation and characterization of polypyrrole/dextran sulphate composite: its electrochemical and thermal behaviors
    (Springer, 2015) Yalcinkaya, Suleyman; Demirbilek, Celile; Dinc, Cemile Ozdemir
    Polypyrrole/dextran sulphate (PPy/Dx-SO4) composite was synthesized in 1 M HCl medium by chemical polymerization method. The synthesized composite was characterized using H-1-NMR, UV-Vis, FT-IR, SEM micrographs, cyclic voltammetry, TG-DTA and viscosity measurements. The SEM micrographs were clearly indicated that PPy, Dx-SO4 and PPy/Dx-SO4 composite have different morphology. The composite architecture is also seen alike as globular and agglomerate particles. The composite has better thermal stability than Dx-SO4. The results of the solubility studies indicated that the composite partially dissolved in DMSO, DMF, and NMP. Additionally, the composite was more soluble in these solvents than PPy, providing technological usefulness. The electrochemical studies showed that PPy/Dx-SO4 composite has low electrical conductivity, but it has good electrochemical stability than PPy.
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    Solubility Profiles of Poly(ethylene glycol)/Solvent Systems. II. Comparison of Thermodynamic Parameters from Viscosity Measurements
    (Wiley, 2010) Dinc, Cemile Ozdemir; Kibarer, Guenay; Guner, Ali
    Solution thermodynamics of PEG samples in aqueous and nonaqueous (methanol, chloroform, tetrahydrofuran, and dimethylsulfoxide) solutions have been investigated by viscometric studies at 25, 30, 35, and 40 degrees C. The hydrodynamic expansion factor, a(h), and the unperturbed root mean square end-to-end distance, < r(2)>(1/2)(theta), found for the system indicated that the polymer coils contract as the temperature is raised. The long-range interaction parameter, B, was also evaluated and a significant decrease with increasing temperature was observed. The theta temperatures, theta, obtained from the temperature dependence of (1/2 - chi) and the second virial coefficient, A(2), are quite good in agreement with the calculated values evaluated via extrapolation and interpolation methods. The thermodynamic interaction parameter, x, was evaluated through the sum of the individual values of enthalpy and entropy dilution parameters for PEG samples. The restrictions applying to the establishment of concentration regimes, short-range, and long-range interactions are discussed. A parallelism is found between solubility profiles obtained by solution viscometry and solubility parameter approaches for PEG/solvent systems. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 1100-1119, 2010
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    Synthesis and characterization of poly(m-aminophenol)-succinat
    (Taylor & Francis Ltd, 2014) Dinc, Cemile Ozdemir; Yalcinkaya, Suleyman; Altuntas, Hazal; Colak, Nureddin
    Poly(m-aminophenol) (PMAP) and poly(m-aminophenol)-succinat compound (PMAP-Suc) containing ester bridge were synthesized in this study. PMAP were synthesized by chemical oxidative polymerization of m-aminophenol (MAP) in HCl medium with ammonium peroxydisulphate (APS) as an initiator at different temperatures. The optimum polymerization conditions (temperature: 25 degrees C, reaction time: 4 h, normalized MAP/APS ratio, k: 0.625 and mol of MAP/mol of APS, r: 0.5) of PMAP were determined. PMAP was esterified in N-methyl pyrrolidone by using solution of succinic acid as cross-linking agent and concentrated sulphuric acid as catalyst under appropriate ambient conditions. The general scheme of esterification and cross-linking reaction for PMAP is proposed. These reactions were also evidenced by spectroscopic, thermal and surface morphology as well as structural characteristics relationship of macromolecules. The structures of PMAP and PMAP-Suc were characterized by solubility test, FTIR, H-1 NMR and C-13 NMR, UV-vis spectroscopy, thermal (TGA-DTA) and SEM analyses.
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    Synthesis of diethylaminoethyl dextran hydrogel and its heavy metal ion adsorption characteristics
    (Elsevier Sci Ltd, 2012) Demirbilek, Celile; Dinc, Cemile Ozdemir
    Epichlorohydrin-crosslinked diethylaminoethyl dextran (DEAE-D/ECH) hydrogel was synthesized by intermolecular side-chain reaction of DEAE-D hydroxyl groups with monomeric crosslinking agent, ECH. Swelling ability, adsorption capacity and metal removal of the hydrogel were profoundly determined and some structural parameters for the hydrogel such as volume of non-swollen gel, percentages of gellation, swelling ratio and equilibrium water content were evaluated in this study. The ability of removing heavy metal ions from Orontes River by the synthesized hydrogel, thoroughly characterized by photometric spectrometer and the adsorption characteristics of metal ions, was investigated as well as surface morphologies of the hydrogel before and after metal adsorption were examined by SEM. Structure of DEAE-D/ECH gel was analyzed by FTIR, TGA, and DSC. Gellation point of binary system reaction between DEAE-D and ECH was determined via monitoring viscosity changes during reaction. The order of affinity based on amount of metal ion uptake was found as follows: Zn2+ > Mn2+ > Pb2+ > Cd2+. (C) 2012 Elsevier Ltd. All rights reserved.