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 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 polybenzoxazine precursors using thiols: Simultaneous thiol-ene and ring-opening reactions(2012-10-01T00:00:00Z) Beyazkilic, Zeynep; Kahveci, Muhammet Übeydullah; Aydogan, BİNNUR; Kışkan, Barış; Yağcı, Yusuf; TEMEL, BİNNURA new class of polybenzoxazine precursors of combined molecular structure of benzoxazine in the open and ring form has been developed. Thermally curable benzoxazine networks were obtained by simultaneous photoinduced thiol-ene and Catalytic Opening of the Lateral Benzoxazine Rings by Thiols (COLBERT). The thiol-ene reactions were initiated by photolysis of a free radical photoinitiator, 2, 2-dimethoxy-2-phenyl acetophenone (DMPA), and the competing COLBERT reaction was triggered by thiol compound, 1,2-ethanedithiol, present in the reaction mixture. The extent of reactions was evaluated by conducting experiments both under UV irradiation and in dark using model benzoxazines. The precursor soft films (pre-P(B-ala-DTE)) were prepared by irradiating solutions of diallyl functional benzoxazine (B-ala), 1,2-ethanedithiol and DMPA. The obtained pre-P(B-ala-DTE) films were then cured through thermally activated ring opening reaction of remaining benzoxazine groups yielding a more rigid and tough film. Thermal and mechanical properties of the films were investigated by DSC, DMA and TGA and compared with a typical polybenzoxazine, P(B-ala). (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012Publication Metadata only Thermal degradation of polysiloxane and polyetherester containing benzoxazine moieties in the main chain(2011-03-01T00:00:00Z) Bagherifam, Shahla; Kışkan, Barış; Aydogan, BİNNUR; Yağcı, Yusuf; HACALOĞLU, JALE; TEMEL, BİNNURIn this study investigation of thermal characteristics of polysiloxane and polyetherester containing benzoxazine moieties in the main chain was performed via pyrolysis mass spectrometry. Pyrolysis mass spectrometry analyses revealed that the thermal stability and the extent of cross-linking enhanced when the benzoxazine moieties were separated by thermally more stable units such as siloxanes. However, when the siloxane chain units were long, possibility of polybenzoxazine growth decreased significantly and benzoxazine moieties were evolved in the temperature range where polysiloxane degradation took place. (C) 2010 Elsevier B.V. All rights reserved.