Person: KAHRAMAN, MEMET VEZİR
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KAHRAMAN
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MEMET VEZİR
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Publication Metadata only Synthesis and characterization of UV-curable dual hybrid oligomers based on epoxy acrylate containing pendant alkoxysilane groups(ELSEVIER SCIENCE SA, 2006) KAHRAMAN, MEMET VEZİR; Bayramoglu, Gulay; Kahraman, M. Vezir; Kayaman-Apohan, Nilhan; Gungor, AtillaThis work involves the synthesis of novel hybrid oligomers based on a UV-curable epoxy acrylate resin (EA). The EA resin was modified with various amount of 3-isocyanatopropyl trimethoxysilane (IPTMS) coupling agent. The modification percentage of the hybrid oligomer was varied from 0 to 50 wt.%. UV-curable, hard and transparent organic-inorganic hybrid coatings were prepared on Plexiglas substrates and their characterization was performed by the analyses of various properties such as hardness, gloss, tape adhesion test and stress-strain test. Results from the mechanical measurements show that the properties of hybrid coatings improve with the increase in modification ratio. The thermal behavior of coatings was also evaluated. It is observed that the thermal stability of epoxy acrylate coatings is enhanced with incorporation of siloxane. Gas chromatography/mass spectrometry analyses showed that the initial weight loss obtained in thermogravimetric analysis is due to the degradation products of the photoinitator and the acrylic acid moiety of acrylic monomers. (c) 2006 Elsevier B.V. All rights reserved.Publication Metadata only Sulfathiazole-based novel UV-cured hydrogel sorbents for mercury removal from aqueous solutions(PERGAMON-ELSEVIER SCIENCE LTD, 2009) KÖK YETİMOĞLU, ECE; Yetimoglu, Ece Koek; Kahraman, Memet Vezir; Bayramoglu, Guelay; Ercan, Oezgen; Apohan, Nilhan KayamanSulfathiazole-based novel hydrogel sorbents P(Sulti/hydroxyethyl methacrylate (HEMA)/acrylic acid (AAc)) were prepared by UV irradiation and used for the removal of mercury(II) ion from aqueous media. Hydrogels have been characterized by SEM and thermogravimetric analysis (TGA) techniques. The influence of the uptake conditions was investigated; maximum Hg(II) ion adsorption capacity obtained was 13.46 +/- 1.15mg g(-1) at pH 5.0. The hydrogels were tested several times without loss of adsorption capacity. The selectivity of the hydrogel towards to Hg(II), Cd(II) and Zn(II) ions tested was Hg>Cd>Zn. (C) 2008 Elsevier Ltd. All rights reserved.Publication Metadata only Preparation and characterization of light curable hybrid coating: Its potential application for dental restorative material(SPRINGER, 2008) KAHRAMAN, MEMET VEZİR; Guengoer, Atilla; Kayaman-Apohan, Nilhan; Mert, Ayse; Kahraman, M. VezirThe objective of this study was to synthesize a dual-functional light curable resin by the reaction between acrylated cycloaliphatic epoxy resin and 3-isocyanatopropyltrimethoxysilane and investigate the performance of this oligomer in the preparation of resin-based composite restoratives. FT-IR and (29)Si-NMR were used to characterize the structure of the hybrids. The char yields of the hybrids increased with inorganic content comes from TEOS (tetraethylorthosilicate) and synthesized SiUA oligomers. Gel content of polymeric films was found to be between 95% and 98%. Swelling was found to be between 3.1% and 3.8%. Weight loss of coated human teeth in synthetic saliva solution was found to be among 1% and 2%. There was a systematic increase in the modulus and tensile strength with the increase of inorganic content. On the other hand, elongation at break did not changed. Prepared hybrid coating materials exhibited improvement in tensile properties and hardness, when photo chemically cured.Publication Metadata only Preparation and Characterization of UV-Curable, Boron-Containing, Transparent Hybrid Coatings(WILEY, 2011) KAHRAMAN, MEMET VEZİR; Mulazim, Yusuf; Kahraman, Memet Vezir; Apohan, Nilhan Kayaman; Kiziltas, Sahip; Gungor, AtillaA series of ultraviolet (UV)-curable, boron-containing hybrid coatings were prepared by an anhydrous sol-gel technique from a mixture of an acrylated bisphenol A based epoxy resin, methacryloxymethyl triethoxysilane, and boric acid. The use of boric acid allowed the hydrolysis and condensation of hybrid silicon alkoxides without the further addition of water or a catalyst. The chemical structure of the boron-containing hybrid coatings was characterized with Fourier transform infrared, real-time infrared, and Si-29 cross-polarization/magic-angle spinning NMR techniques. UV-curable coatings were applied to polycarbonate and Plexiglas substrates. The physical and mechanical properties of the UV-cured coatings (e.g., pendulum hardness, pencil hardness, con-tact angle, gel content, methyl ethyl ketone rubbing test, tensile test, abrasion resistance, chemical resistance, neutron absorption, and limiting oxygen index) were examined. The hybrid coatings showed a significant enhancement in their radiation-shielding properties. The thermal behavior of the coatings was also evaluated. It was observed that the thermal stability of the coatings mainly depended on their boron and silicate contents. The results of all analyses of the free films and coatings were examined. VC 2010 Wiley Periodicals, (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 2112-2121, 2011Publication Metadata only The coating performance of adipic acid modified and methacrylated bisphenol - A based epoxy oligomers(WILEY, 2007) KAHRAMAN, MEMET VEZİR; Bayramoglu, Guelay; Kahraman, M. Vezir; Kayaman-Apohan, Nilhan; Guengoer, AtillaIn the present work adipic acid modified and methacrylated bisphenol A based epoxy resins were prepared. The structures of oligomers were characterized by FT-IR. UV curable clear coatings were applied on aluminum substrates. The physical and mechanical properties of UV-cured coatings such as gel content, solvent resistance, hardness, gloss, flexibility and tensile tests were examined. In addition, the thermal behavior of coatings was also evaluated. It is observed that the tensile properties and thermal stabilities of modified epoxy methacrylate coatings mainly depend on the adipic acid content. The best results were obtained with 5 wt% adipic acid modification. Copyright (C) 2007 John Wiley & Sons, Ltd.Publication Metadata only UV cured thiol-ene flame retardant hybrid coatings(ELSEVIER SCIENCE SA, 2013) OKTAY, BURCU; Basturk, Emre; Oktay, Burcu; Kahraman, Memet Vezir; Apohan, Nilhan KayamanIn this study, bis-(triethoxysilylpropyl) phenyl phosphamide (BESPPA) was synthesized by the reaction between dichlorophenyl phosphine oxide and 3-aminopropyltriethoxysilane. The chemical structure of the BESPPA was characterized with Fourier transform infrared and NMR techniques. Flame retardant, BESPPA and sol gel precursor containing hybrid materials were prepared by thiol-ene polymerization with the aim to improve their final thermal and flame retardant properties. The thermal stabilities of the phosphorous/sol-gel containing UV-cured hybrid materials were investigated by thermogravimetric analysis. The results showed that the addition of sol-gel precursor and BESPPA into the organic network also improves the thermal-oxidative stability of the hybrid materials. The flame-retardant properties of the UV-cured hybrid materials were also studied. Furthermore, the phosphorus silicon synergistic effect on LOI enhancement and increasing flame retardancy of the UV-cured hybrid materials were demonstrated. An LOI enhancement from 20.7 to 26.5 is observed for organic resins containing both phosphorus and silicon. 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) 2012 Elsevier B.V. All rights reserved.