Person: TEMEL, BİNNUR
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Publication Metadata only Thermally curable main-chain benzoxazine prepolymers via polycondensation route(2013-02-01T00:00:00Z) Demir, Kubra Dogan; Kışkan, Barış; Aydogan, BİNNUR; Yağcı, Yusuf; TEMEL, BİNNURPolybenzoxazines are addition-cure thermosetting polymers exhibiting versatility in a wide range of applications due to their good mechanical properties, dimensional stability, chemical resistivity, flame resistance property phenolic or epoxy resins have myriad applications in diverse fields starting from commodity materials to high technology aerospace industries. In this paper, we present synthetic strategies to incorporate thermally curable benzoxazine functionality into polymers as main-chain fashion in order to further improve various properties. The strategies successfully employed including monomer synthesis and polycondensation routes like Mannich reaction, click chemistry, hydrosilylations, and coupling reactions. The structure-property relationships of the cured materials have also been presented and discussed. (C) 2012 Elsevier Ltd. All rights reserved.Publication Metadata only Single-Chain Folding Nanoparticles as Carbon Nanotube Catchers(2018-12-15T00:00:00Z) BİLGİ, Mesut; Balta, Demet Karaca; Temel, Binnur Aydogan; Temel, Gokhan; TEMEL, BİNNURThis contribution describes a simple method for preparing polymeric nanoparticles using photodimerization of anthracene moieties on the side chain of terpolymers in dilute regime and transformation of obtained polymeric nanoparticles into pyrene functional nanoparticles via Menschutkin quaternization procedure. Subsequently, pyrene possessing polymeric nanoparticles are attached onto multiwalled carbon nanotube (MWCNT) surfaces by pi-pi stacking strategy. Gel permeation chromatography, thermal gravimetric analysis, ultraviolet-visible, and fluorescence spectroscopies are used to analyze modified nanoparticles and their precursors. Electron microscopy and dispersion studies show that pyrene-modified polymeric nanoparticles are able to interconnect various CNTs. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2709-2714Publication Metadata only Photoinduced Electron Transfer Reactions of Highly Conjugated Thiophenes for Initiation of Cationic Polymerization and Conjugated Polymer Formation(2012-10-09T00:00:00Z) Aydogan, BİNNUR; Yağcı, Yusuf; Toppare, Levent; Jockusch, Steffen; Turro, Nicholas J.; TEMEL, BİNNURPhotoinduced electron transfer reactions of highly conjugated thiophene derivatives, 4,7-di(2,3-dihydrothieno[3,4-b] [1,4]dioxin-5-yl)benzo[1,2,5]thiadiazole (DTDT) and 5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,3-di(thiophen-2-yl)quinoxaline (DTDQ), with diphenyl-iodonium hexafluorophosphate (Ph2I+PF6-) and triphenylsulfonium hexafluorophosphate (Ph3S+PF6-) were investigated by laser flash photolysis, fluorescence and phosphorescence spectroscopy, and polymerization studies. High fluorescence quantum yields, long fluorescence lifetimes (similar to 10 ns in aprotic solvents), and absence of detectable phosphorescence at 77 K for both compounds indicate inefficient intersystem crossing into the triplet state and dominant role of singlet excited state. Photolysis of DTDT or DTDQ in the presence of iodonium salt with visible light results in the formation of radical cations of DTDT and DTDQ as detected by laser flash photolysis. Sulfonium salts do not undergo such electron transfer reactions due to the unfavorable redox potentials. The importance of the described photoinduced electron transfer process with respect to the initiation of cationic polymerization and formation of conjugated polymers was demonstrated.Publication Metadata only Academicians Perspective for the Application Requirements to the Graduate Programs, Education and Functioning of the Institute of Health Sciences in Bezmialem Vakif University(2018-05-26) ÖZÇELİK, SEMRA; TEMEL, BİNNUR; ÖZÇELİK, SEMRA; TEMEL, BİNNURPublication Metadata only Long wavelength photoinitiated free radical polymerization using conjugated thiophene derivatives in the presence of onium salts(2011-01-01T00:00:00Z) Beyazit, Selim; Aydogan, BİNNUR; Osken, Ipek; Öztürk, Turan; Yağcı, Yusuf; TEMEL, BİNNURLong wavelength free radical photopolymerization of (meth) acrylic monomers using a conjugated thiophene derivative, namely 3,5-diphenyldithieno[3,2-b: 2-,3--d]-thiophene (DDT) and one of the following compounds, namely diphenyliodonium hexafluorophosphate (Ph(2)I(+)PF(6)(-)), triphenylsulfonium hexafluorophosphate (Ph(3)S(+)PF(6)(-)) and N-ethoxy-2-methylpyridinium hexafluorophosphate (EMP(+)PF(6)(-)), as photosensitizer and coinitiator, respectively, was described. Polymerization occurred only when DDT, in the presence of the onium salts, was irradiated at wavelengths where the salts have no absorption. A feasible initiation mechanism involves intermolecular electron transfer from photoexcited thiophene compound to the onium salt. The relative initiation efficiencies of the salts were investigated and evaluated in terms of their redox potentials.Publication Metadata only Covalent Immobilization of Furanone Derivatives for the Inhibition of Biofilm Formation on Implant Surfaces(2018-04-01) Yelboğa, Emrah; TEMEL, BİNNUR; Karagüler, Nevin Gül; Tüter, Melek; TEMEL, BİNNURPublication Metadata only Bir Üniversitenin Girişimsel Olmayan Araştırmalar Etik Kuruluna Yapılan Başvurularda Eksiklikler ve Sıklıkla Yapılan Hatalar(2019-08-01) Meral, İsmail; Aştı, Türkinaz; Soysal, Ömer; Yıldırım, Nuran; Özçelik, Semra; Aydın, Teoman; Akbaş, Fahri; Temel, Binnur; Özder, Aclan; Büyükpınarbaşılı, Nur; Dönmez, Nazmiye; Alkaya, Mustafa Fırat; MERAL, İSMAİL; AŞTI, TÜRKINAZ; SOYSAL, ÖMER; YILDIRIM, NURAN; ÖZÇELİK, SEMRA; AYDIN, TEOMAN; AKBAŞ, FAHRİ; TEMEL, BİNNUR; ÖZDER, ACLAN; BÜYÜKPINARBAŞILI, NUR; DÖNMEZ, NAZMİYEGirişimsel olmayan araştırmalarda, ilgili etik kurulun onayını almadan çalışmalara başlamak mümkün değildir. Dünya Sağlık Örgütü-nün kurallarına göre, gerekli tüm belgeleri içeren başvuru dosyası ilgili Etik Kurula eksiksiz sunulmalıdır. Araştırmacıların başvuru dosyasındaki belgeleri eksiksiz tamamlamadaki isteksizliği, Etik Kurulların çalışma sürecini yavaşlatmakta ve hatta Etik Kurul ile araştırmacılar arasında tartışmaya bile neden olabilmektedir. Bu nedenle bu çalışma, bir üniversitenin Girişimsel Olmayan Araştırmalar Etik Kuruluna gönderilen proje başvuru dosyalarındaki eksiklikleri ve en çok yapılan hataları göstermek ve araştırmacılar için bir rehber oluşturmak amacıyla yapıldı. 24 Mart 2016 ve 30 Haziran 2018 tarihleri arasında Girişimsel Olmayan Araştırmalar Etik Kurula gönderilen başvuru dosyaları ve kararları ilgili etik kurulun veri tabanından analiz edildi. Başvuru dosyalarının revizyonuna neden olan en önemli gerekçeler, projenin amacının ilgili referanslar eşliğinde yeterince açıklanamaması ve özellikle iyi yazılamamış yöntem kısmı gibi başvuru formundaki eksikliklerdi. Araştırmacıları proje başvuru dosyası hazırlarken en çok yapılan hatalar hakkında eğitmek, Üniversite Etik Kurullarının gözden geçirme sürecinin verimliliğini ve hızını artıracaktır.Publication Metadata only Thioxanthone-Fluorenes as Visible Light Photoinitiators for Free Radical Polymerization(2010-05-25T00:00:00Z) Yilmaz, Gorkem; Aydogan, Binnur; Temel, Gokhan; ARSU, Nergis; MOSZNER, Norbert; Yağcı, Yusuf; TEMEL, BİNNURTwo thioxanthone derivatives with fluorene additional chromophoric groups, namely thioxanthone-fluorenecarboxylie acid (TX-FLCOOH) and thioxanthone fluorene sodium carboxylate (TX-FLCOONa), as visible light absorbing oil- and water-soluble photoinitiators, respectively, were synthesized and characterized. Their ability to initiate photopolymerization of methyl methacrylate (M MA), 2-(2-phosphonoethoxymethyl)acrylic acid ethyl ester (EAEPA), and a multifunctional monomer, trimethylolpropane triacrylate (TMPTA), were examined. The initiation efficiency of TX-FLCOOH was compared with the parent thioxantone (TX) both in the presence and in the absence of a co-initiator, and TX-FLCOOH was found to be more effective in :ill cases. Photopolymerization and laser flash photolysis studies revealed that depending on the concentration initiation by TX-FLCOOH occurs by intra and intermolecular H-abstraction of the triplet (3)(TX-FLCOOH)*. No polymerization was observed when TX-FLCOONa was used as photoinitiator in the absence of a co-initiator. However, TX-FLCOONa acts as an efficient initiator in the visible range in the presence of H donors in water.Publication Metadata only Polysiloxane-Containing Benzoxazine Moieties in the Main Chain(2010-11-15T00:00:00Z) Aydogan, BİNNUR; Sureka, Dilek; Kışkan, Barış; Yağcı, Yusuf; TEMEL, BİNNURPolysiloxanes containing thermally curable benzoxazine units in the main chain have been synthesized. For this purpose, first the diallyl functional benzoxazine monomer is synthesized through the Mannich and respective ring closing reactions of 4,4--isopropylidenediphenol (bisphenol A), formaldehyde, and allyamine. Subsequent hydrosilylation reaction of the resulting allylic monomer (B-ala) with 1,1,3,3-tetramethyldi-siloxane (TMDS) in the presence of Pt catalyst yields the corresponding oligo(B-ala-tetramethyldisiloxane)s (OBTMDS). Using the anionic polymerization route, OBTMDS was then converted to poly(bisbenzoxazinedimethylsiloxane)s (PBDMSs) by reacting with readily available cyclic oligomer octamethylcyclotetrasiloxane (D4) or decamethylcyclopentasiloxane (D5) in the presence of tetrabutylammonium hydroxide as catalyst. The structures of the precursor diallyl monomer, the intermediate oligomer, and the resulting polymers are confirmed by Fourier transform infrared and H-1 NMR analysis. Curing behavior of the products at various stages has also been studied by differential scanning calorimetry. Flexible transparent films of the PBDMSs are obtained by solvent casting. Thermal properties of the cured polymers are also investigated by thermogravimetric analysis. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5156-5162, 2010Publication Metadata only Synthesis of H-Shaped Complex Macromolecular Structures by Combination of Atom Transfer Radical Polymerization, Photoinduced Radical Coupling, Ring-Opening Polymerization, and Iniferter Processes(2013-11-01) Temel, BİNNUR; AMICI, Julia; SANGERMANO, Marco; Yağcı, Yusuf; TEMEL, BİNNURThree controlled/living polymerization processes, namely atom transfer radical polymerization (ATRP), ring-opening polymerization (ROP) and iniferter polymerization, and photoinduced radical coupling reaction were combined for the preparation of ABCBD-type H-shaped complex copolymer. First, -benzophenone functional polystyrene (BP-PS) and poly(methyl methacrylate) (BP-PMMA) were prepared independently by ATRP. The resulting polymers were irradiated to form ketyl radicals by hydrogen abstraction of the excited benzophenone moieties present at each chain end. Coupling of these radicals resulted in the formation of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) with benzpinacole structure at the junction point possessing both hydroxyl and iniferter functionalities. ROP of epsilon-caprolactone (CL) by using PS-b-PMMA as bifunctional initiator, in the presence of stannous octoate yielded the corresponding tetrablock copolymer, PCL-PS-PMMA-PCL. Finally, the polymerization of tert-butyl acrylate (tBA) via iniferter process gave the targeted H-shaped block copolymer. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4601-4607