Person: KAHRAMAN, MEMET VEZİR
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KAHRAMAN
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MEMET VEZİR
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Publication Metadata only Quaternary imidazolium-functionalized reactive silica nanoparticles-containing thiol-ene photocured antibacterial hybrid coatings(Elsevier B.V., 2022) ÇAKMAKÇI, EMRAH; Şen F., Kocatürk E., Çakmakçı E., Kahraman M.V.The need for antibacterial coatings is increasing day by day. In this study, coating materials that do not contain antibacterial agents but have antibacterial properties have been developed. First, two different quaternary imidazole compounds were synthesized. Then, silica nanoparticles were modified with these quaternary agents. By using 1%, 3% and 5% modified silica nanoparticles, UV cured coating materials were obtained according to the thiol-ene reaction mechanism. Mechanical, thermal, surface, structural, optical and antibacterial analyzes of the obtained coatings were performed. The analyzes revealed that UV cured antibacterial coating materials have been successfully synthesized and can be used as a new and unique coating material for the coating industry. © 2021 Elsevier B.V.Publication Metadata only Thermal, optical and electrical properties of UV-curing screen-printed glass substrates(SPRINGER, 2019) ARMAN KANDIRMAZ, EMİNE; Cigil, Asli Beyler; Kandirmaz, Emine Arman; Birtane, Hatice; Kahraman, Memet VezirIn this study, the hydroxyl functionality of the polyaniline surface was obtained using hydroxyethyl methacrylate and acrylated with isocyanatoethyl methacrylate. Coating formulation being curable with UV was designed by mixture of acrylated PANI (a-PANI) (0-5wt%), polyethylene glycol diacrylate, trimethylolpropane triacrylate, hydrolyzed 3-(methacryloxy) propyl trimethoxysilane (hydMEMO) and photoinitiator. The hybrid composite formulation has been printed on the glass surface with the method of screen printing. The chemical structure and the properties of thermal, electrical and surface obtained products were determined with ATR-FTIR, goniometer, current-voltage meter, scanning electron microscopy (SEM) and thermogravimetric analysis. ATR-FTIR results have shown that all materials were clearly produced. SEM results have revealed that PANI was dispersed at the composite in a stable manner. The conductivity value of the conductive line printed with F5a-PANI was found to be 3.7x10(-3)S. The best electrical results have presented that PANI has been beneficial for conductive line, and thus, screen printing was a convenient method for printing conductive lines.Publication Metadata only Preparation and electrical properties of polypyrrole containing photocured thiol-ene based composites(ELSEVIER SCIENCE SA, 2015) DUMLUDAĞ, FATİH; Madakbas, Seyfullah; Dumludag, Fatih; Eminoglu, Elif Merve; Sen, Ferhat; Kahraman, Memet VezirIn this study, UV curable polypyrrole containing thiol ene based composite films were prepared by the reaction between Propoxylated (2) neopentyl glycol diacrylate (SR 9003), Trimethylolpropane tris(3-mercaptopropionate), (3-mercaptopropyl)trimethoxysilane, 1-vinyl-2-pyrrolidinone and polypyrrole. FT-IR was used to confirm the formation of the composites. Thermal stability of the samples was evaluated by thermogravimetric analysis (TGA). The samples were characterized with the following analysis; gel content, water absorption capacity. Hydrophobicity of the samples was determined by the contact angle measurements. Direct current (dc) conductivity measurements of samples were performed depending on polypyrrole content in the composites at room temperature. Capacitance measurements (40 Hz-100 kHz) of the samples were performed in the temperature range of 295-378 K. Dc conductivity and capacitance values of the samples were measured in vacuum in dark. Dc conductivity measurements revealed that dc conductivity values increased with increasing polypyrrole content. Dielectric measurements revealed that dielectric constant of the samples increased with increasing temperature and decreased with increasing frequency. It is also observed that dielectric constant of the samples decreased with increasing polypyrrole content. (C) 2014 Elsevier B.V. All rights reserved.Publication Metadata only Preparation and characterization of boron containing thiol-ene photocured hybrid coatings(ELSEVIER SCIENCE SA, 2012) ÇAKMAKÇI, EMRAH; Cakmakci, Emrah; Mulazim, Yusuf; Kahraman, Memet Vezir; Apohan, Nilhan KayamanIn this study, flame retardant, 4-vinylphenyl boronic acid containing coatings were prepared by thiol-ene polymerization. The photopolymerization kinetics of thiol-ene based formulations was investigated by real time infrared spectroscopy. The experiments showed that as the amount of boronic acid was increased, flame retardant properties of the coatings were also increased. Tensile test results showed that boronic acid groups strengthened the polymeric network. DSC results revealed that the addition of thiol causes Tg values of the coatings to decrease. On the other hand acid groups improved the hydrophilicity of the coatings. (C) 2012 Elsevier B.V. All rights reserved.Publication Metadata only Recovery of Au(III) ions by Au(III)-imprinted hydrogel(SPRINGER INTERNATIONAL PUBLISHING AG, 2016) KÖK YETİMOĞLU, ECE; Firlak, Melike; Cubuk, Soner; Yetimoglu, Ece Kok; Kahraman, Memet V.A new Au(III)-imprinted hydrogel (Au(III)-Imp) was prepared by the photopolymerisation of 4-acryloylmorpholine (AcM), 2-hydroxyethyl acrylate (HEA), and poly(ethylene glycol) diacrylate (cross-linking monomer, PEG-DA) in the presence of gold ions. In addition, non-imprinted hydrogel (N-Imp) was similarly prepared without Au(III) ions The Au(III)-Imp hydrogel was characterised by several techniques. To achieve the optimal conditions, effect of pH, time, and initial metal ion concentrations were investigated using a batch system. The pre-concentration factor for Au(III) ions was found to be at least 100. The analytical parameters of the method were determined and the method was also successfully applied to computer circuit board scrap samples. The reusability of the Au(III)-Imp hydrogel was also determined. (C) 2016 Institute of Chemistry, Slovak Academy of SciencesPublication Metadata only 4-Vinylbenzene Boronic Acid-Hydroxy Apatite/Polyvinyl Alcohol Based Nanofiber Scaffold Synthesized by UV-Activated Reactive Electrospinning(TAYLOR & FRANCIS AS, 2015) KAHRAMAN, MEMET VEZİR; Deniz, D. Yuksel; Kahraman, M. V.; Erdem Kuruca, S.; Suleymanoglu, M.; Gungor, A.In this study, we prepared photo-crosslinked modified HAP (hydroxy apatite)/polyvinyl alcohol (PVA) composite nanofiber scaffold for cell growth applications. HAP was synthesized and then modified with 4-vinylbenzene boronic acid (VBBA) to obtain 4-VBBA-HAP. By means of the simultaneous UV electrospinning technique 4-VBBA-HAP/PVA composite was obtained. The structure and morphology of electrospun membranes were investigated by scanning electron microscopy) and Fourier transform infrared spectroscopy technique. Nanofibers were treated with collagen solution via the spraying method. For the cell culture applications ECV304 and SAOS cells were seeded on the chosen electrospun fibrous scaffolds. [GRAPHICS] .Publication Metadata only Alpha-Amylase Immobilization on Epoxy Containing Thiol-Ene Photocurable Materials(KOREAN SOC MICROBIOLOGY & BIOTECHNOLOGY, 2013) ÇAKMAKÇI, EMRAH; Cakmakci, Emrah; Danis, Ozkan; Demir, Serap; Mulazim, Yusuf; Kahraman, Memet VezirThiol-ene polymerization is a versatile tool for several applications. Here we report the preparation of epoxide groups containing thiol-ene photocurable polymeric support and the covalent immobilization of alpha-amylase onto these polymeric materials. The morphology of the polymeric support was characterized by scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) coupled with SEM was used to explore the chemical composition. The polymeric support and the immobilization of the enzyme were characterized by FTIR analysis. SEM-EDS and FTIR results showed that the enzyme was successfully covalently attached to the polymeric support. The immobilization efficiency and enzyme activity of alpha-amylase were examined at various pH (5.0-8.0) and temperature (30-80 degrees C) values. The storage stability and reusability of immobilized alpha-amylase were investigated. The immobilization yield was 276 +/- 1.6 mg per gram of polymeric support. Enzyme assays demonstrated that the immobilized enzyme exhibited better thermostability than the free one. The storage stability and reusability were improved by the immobilization on this enzyme support. Free enzyme lost its activity completely within 15 days. On the other hand, the immobilized enzyme retained 86.7% of its activity after 30 days. These results confirm that alpha-amylase was successfully immobilized and gained a more stable character compared with the free one.Publication Metadata only Flame retardant thiol-ene photocured coatings(ELSEVIER, 2011) ÇAKMAKÇI, EMRAH; Cakmakci, Emrah; Mulazim, Yusuf; Kahraman, Memet Vezir; Apohan, Nilhan KayamanThe low polymerization tendency of allyl compounds can be enhanced by thiol-ene polymerization systems. In this study. allyldiphenyl phosphine oxide (ADPPO) containing thiol-ene based photocured coatings were prepared with the aim to improve their final thermal and flame retardant properties. The photopolymerization kinetics of thiol-ene based formulations were investigated by real-time infrared spectroscopy. The incorporation of ADPPO into the polymer chains was confirmed by monitoring the conversion of acrylate double bonds and measuring the gel content of the crosslinked films. The experiments showed that as the amount of ADPPO was increased, thermal and flame retardant properties of the coatings were also increased. (C) 2010 Elsevier Ltd. All rights reserved.Publication Metadata only Synthesis of fluorinated/methacrylated epoxy based oligomers and investigation of its performance in the UV curable hybrid coatings(ELSEVIER SCIENCE SA, 2009) KAHRAMAN, MEMET VEZİR; Kahraman, Memet Vezir; Bayramoglu, Guelay; Boztoprak, Yalcin; Gungor, Atilla; Kayaman-Apohan, NilhanOrganic-inorganic hybrid coatings based on fluorinated/methacrylated soybean oil and bisphenol A/F epoxy methacrylate were obtained by combining photopolymerization and sol-gel process. Hard and transparent hybrid coatings were prepared on polycarbonate panels and their physical and mechanical properties such as gel content, hardness, adhesion, gloss, contact angle as well as tensile strength were measured. Results from the mechanical measurements showed that the properties of hybrid coatings improved with the increase in fluorine and sol-gel precursor contents. Thermo gravimetric analysis results demonstrated that fluorine and silica incorporations significantly enhanced the thermal oxidative stability of the hybrid coating materials. The surface morphology was also characterized by scanning electron microscopy (SEM). SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix. (C) 2009 Elsevier B.V. All rights reserved.Publication Metadata only Uptake of Pb2+ Using N-Vinyl Imidazole Based Uniform Porous Hydrogels(TAYLOR & FRANCIS INC, 2011) KÖK YETİMOĞLU, ECE; Firlak, Melike; Cubuk, Soner; Yetimoglu, Ece Kok; Kahraman, Memet VezirThe uniform porous and continuous phase lead (II) adsorbent hydrogel, was prepared by copolymerizing 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AAc), and N,N'-methylenebisacrylamide (MBAAm), with n-vinyl imidazole (VIM). A series of hydrogels, including different ratios of VIM, were prepared by photopolymerization and characterized. The influence of the uptake conditions such as pH, functional monomer percent, contact time, initial feed concentration, and foreign metal ions on the metal ion binding capacity of hydrogel, were also tested. The selective chelation of heavy metal ions from synthetic wastewater was also studied. The affinity order on molar basis was observed as follows: Pb (II) > Zn (II) > Cd (II). Chelation behavior of heavy metal ions could be modelled using both the Langmuir and Freundlich isotherms and it was seen that the Langmuir isotherm model was the best fit for the adsorption of Pb (II) ions in P(VIM/AAc/HEMA) hydrogel. Moreover, the limits of detection and the quantification values were determined. Regeneration of the hydrogels was easily performed with 1M HCl and the same hydrogel can be reused five times almost without any loss of adsorption capacity. All these features make P(VIM/AAc/HEMA) hydrogels potential candidate adsorbent for heavy metal removal.