Person: KAHRAMAN, MEMET VEZİR
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KAHRAMAN
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MEMET VEZİR
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Publication Metadata only Highly porous starch/poly(ethylene-alt-maleic anhydride) composite nanofiber mesh(WILEY, 2013) OKTAY, BURCU; Oktay, Burcu; Basturk, Emre; Kayaman-Apohan, Nilhan; Kahraman, Memet VezirIn this study, starch-based hybrid electrospun nanofiber meshes were fabricated by electrospinning. Spinning solutions were prepared by mixing starch and certain amounts of poly(ethylene-alt-maleic anhydride). Starch-based nanofiber meshes became insoluble in water with thermal-induced esterification of hydroxyl groups onto starch backbone. Morphologic and structure analysis of the electrospun nanofiber meshes were investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) techniques. Thermal properties of nanofiber meshes were characterized by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal stability of nanofiber meshes were increased with formation of intermolecular bonds between starch and poly(ethylene-alt-maleic anhydride). POLYM. COMPOS. 34:1321-1324, 2013. (c) 2013 Society of Plastics EngineersPublication Metadata only Designing Coconut Oil Encapsulated Poly(stearyl methacrylate-co-hydroxylethyl metacrylate) Based Microcapsule for Phase Change Materials(WILEY-V C H VERLAG GMBH, 2019) OKTAY, BURCU; Oktay, Burcu; Basturk, Emre; Kahraman, Memet Vezir; Apohan, Nilhan KayamanPhase change material (PCM) is an effective energy storage application, which has a relatively low cost. In this study, bio-based PCMs were prepared by using two techniques: encapsulation and UV-curing. Encapsulated-PCM was synthesized by suspension polymerization with stearyl methacrylate (SMA) and hydroxyethyl methacrylate (HEMA). In encapsulation process, the microcapsules were prepared from poly(stearyl methacrylate-co-hydroxyethyl methacrylate) shell and coconut oil (CO) core. UV-cured form stable PCM was also prepared by radical addition polymerization of stearyl methacrylate, hydroxyethyl methacrylate and coconut oil. In UV-curing process as in the second process, coconut oil was trapped within the polymeric network without covalent bonding. Thermal storage feature of encapsulated-PCM and UV-cured form stable PCM was investigated. The melting enthalpy of encapsulated-PCM is 119J/g, which is higher than both the melting enthalpy of pure coconut oil (106J/g) and UV-cured form stable PCM (47J/g). Moreover, thermal degradation results of PCMs show that the maximum thermal decomposition temperature of encapsulated-PCM increased compared with UV-cured from stable PCM.Publication Metadata only Development of nanofiber based immunosorbent surface for the removal of fluoxetine from breast milk(TAYLOR & FRANCIS AS, 2019) OKTAY, BURCU; Tunali-Akbay, Tugba; Kahraman, Memet Vezir; Oktay, Burcu; Ipekci, Hazal; Kayaman-Apohan, NilhanIn this study, novel bioactive material has been identified for the removal of fluoxetine from breast milk. For this purpose, the poly (vinyl alcohol)/poly (acrylic acid) based nanofiber with an antibody immobilized has been developed. The efficiency of this nanofiber was compared with the control pore glass (CPG) either in milk. The bioactive nanofiber removed fluoxetine significantly higher than the CPG. The efficiency of the fluoxetine removal with the nanofiber was 98% in breast milk. In conclusion, the nanofiber based immunosorbent surface that is developed in this study was found to be efficient for chemical sensing of fluoxetine. [GRAPHICS] .Publication Metadata only Preparation and evaluation of linseed oil based alkyd paints(ELSEVIER SCIENCE SA, 2014) OKTAY, BURCU; Iseri-Caglar, Dondu; Basturk, Emre; Oktay, Burcu; Kahraman, M. VezirAlkyd resins are produced with reaction of oil or fatty oil, polyol and polyacid. Alkyd resins are commonly used in coating and paint industry due to ease of application in changing environmental conditions. Linseed oil based paints executed all requirements of technical properties, drying time, storage properties, simplicity in maintenance, appearance, economy, etc. In this study, linseed oil based alkyd resins having different oil contents were synthesized Paint formulations were prepared by mixing alkyd resin and various additives such as huntite, Aerosil R972, talc, titanium dioxide, dryer, wetting agent and anti-skinning agent. All formulations were applied on paper test plates and were dried at 30 degrees C. The obtained coatings were characterized by pencil hardness test, pendulum hardness test, chemical resistance test, cross-cut test, contact angle and gloss measurement. Also thermal and morphological properties were investigated by thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM) respectively. The thermal stability of the paint materials are improved with by increasing the amount of huntite and Aerosil R972 in the paint compositions. (C) 2013 Elsevier B.V. All rights reserved.Publication Metadata only Thiol-yne photo-clickable electrospun phase change materials for thermal energy storage(ELSEVIER SCIENCE BV, 2018) OKTAY, BURCU; Oktay, Burcu; Basturk, Emre; Kahraman, Memet Vezir; Apohan, Nilhan KayamanFatty acids, fatty acid esters and fatty acid composites have been widely accepted materials as PCMs. In the present work, nanosilica reinforced nanofiber composite was prepared as PCMs. First, polyvinyl alcohol (PVA) and nanosilica was modified with mercaptopropionic acid and 3-(mercaptopropyl)trimethoxysilane respectively and thiolated-PVA-nanosilica nanofibers were prepared by using electrospinning. Stearic acid was used for long chain fatty acid. Then stearic acid was functionalized with propargyl groups to introduce thiol-yne clickable sites. Finally, various amounts of stearic propargyl ester were reacted with thiolated-PVA-nanosilica nanofibers, following to UV-induced thiol-yne click reaction by UV-irradiation at 365 nm between thiol groups of nanofiber and propargyl groups of stearic propargyl ester. The structural characterization was performed by ATR-FTIR spectroscopy. The morphologies of nanofibers after and before modification were investigated by scanning electron microscopy (SEM). It is said that nanofibers have uniform diameter size. Thermal and phase change behaviors of the electrospun nanofibers were investigated. Thiolated-PVA nanofiber showed no phase change behavior. With the addition of stearic propargyl ester increased phase change enthalpy of the PVA nanofibers from 0 J/g to 37 J/g. The freezing cycle phase change enthalpy was also observed and was found between - 13 and - 47 J/g.Publication Metadata only Dual-crosslinked thiol-ene/sol gel hybrid electrospun nanowires: preparation and characterization(SPRINGER, 2015) OKTAY, BURCU; Basturk, Emre; Oktay, Burcu; Kahraman, Memet VezirIn this report, we describe the preparation and characterization of cross-linked electrospun membranes by using a reactive electrospinning. A novel methacrylate functional poly(vinyl alcohol) (M-PVA) was synthesized by reacting PVA and isocyanatoethyl methacrylate (2-ICEMA). The crosslinked membranes were achieved in a simple process at a single step using thiol-ene reaction between M-PVA and 3-mercaptopropyl trimethoxysilane (MPTMS) during the electrospinning process. In order to improve theirs the stability, the crosslinked membranes were also thermally treated. The morphology was characterized by scanning electron microscopy (SEM). The structure of M-PVA was characterized by attenuated total reflectance FT-IR. Morphological investigations show that the resulting membranes have nanowires morphology. The thermal analysis of the electrospun membranes was also investigated. Thermal stability of the membranes was improved with the incorporation of the sol gel precursor. The described method provides novel route for organic-inorganic hybrid membranes.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.Publication Metadata only Preparation and thermal properties of Alkoxy Silane functionalized polyether sulfone/well-defined poly(trimethoxysilyl) propyl methacrylate-based hybrid materials(WILEY, 2018) OKTAY, BURCU; Oktay, Burcu; Basturk, Emre; Kahraman, Memet Vezir; Kayaman-Apohan, NilhanIn this study, novel polyethersulfone (PES) and poly(trimethoxysilyl) propyl methacrylate (PMPS) containing hybrid materials were prepared. PES was functionalized with trimethoxysilane groups by UV-induced grafting reaction. PMPS was synthesized by atom transfer radical polymerization. In the followed process, the functionalized PES mixed with different amount of PMPS, thermally treated to promote sol-gel crosslinking process to prepare the PES-based hybrid materials. The trimethoxysilane grafted PES chains are covalently bonded with the well-defined trimethoxysilane groups of PMPS. The chemical structure of the prepared PES and PMPS is confirmed by Fourier transform infrared analysis. The morphology of the hybrids was investigated by scanning electron microscopy. The results of thermogravimetric analysis show that the thermal stability of the hybrid materials was significantly affected with the addition of PMPS. POLYM. ENG. SCI., 58:1346-1352, 2018. (c) 2017 Society of Plastics Engineers