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Öğe Direct Insertion Mass Spectrometric Analysis of Thermal Degradation of Poly(2-alkyl-2-oxazoline)(Wiley-V C H Verlag Gmbh, 2012) Atilkan, Nurcan; Nur, Yusuf; Hacaloglu, Jale; Schlaad, HelmutDirect pyrolysis mass spectrometry is applied to investigate the thermal behavior of poly(2-isopropyl-2-oxazoline) (PIPOX, a thermoresponsive polymer) and poly[2-(3-butenyl)-2-oxazoline] (PBOX, a clickable polymer). It is found that the thermal degradation of PIPOX is started by a loss of side chains. At slightly higher temperatures the degradation of the polymer backbone occurs by random chain scission processes. In the case of PBOX, vinyl polymerization of the side chains produces chains with variable thermal stabilities. The number of repeating units of the polymer has almost no effect on the thermal behavior of PIPOX, but significantly affects both thermal stability and degradation product distribution of PBOX.Öğe Direct Pyrolysis - Mass Spectrometry Analysis of Thermal Degradation of Thio-Click-Modified Poly(2-oxazoline)(Wiley-V C H Verlag Gmbh, 2014) Atilkan, Nurcan; Schlaad, Helmut; Nur, Yusuf; Hacaloglu, Jale[Abstract Not Available]Öğe Facile Synthesis of SiO2 From Poly(silyne-co-hydridocarbyne) Preceramic Precursor(Springer, 2017) Nur, Yusuf; Bayol, Gizem E.Pre-ceramic polymers have previously been known as polymeric precursors that can be converted to silicon carbide, diamond and diamond-like carbon upon heating at ambient inert atmosphere. Here, we report to demonstrate a novel and simple method for the production of crystalline SiO2 ceramic species using a polymeric precursor, which is poly(silyne-co-hydridocarbyne), upon heating under an ambient air atmosphere. The synthesis of both the polymer and the resulting crystalline ceramic is relatively straightforward and unique. All characterization methods such as Raman and X-ray analysis were showed that SiO2 with a different crystal structure is successfully produced at 1000, 750, and 500 A degrees C under an ambient air atmosphere. In addition, the type of produced SiO2 strictly depends on process temperature. The results also showed that the materials are polycrystalline which is evaluated from the comprehensive XRD analysis. SiO2 produced is the mixture of Tridymite-M, syn and Moganite at 1000 A degrees C, the mixture of Coesite and Tridymite at 750 A degrees C, and the mixture of Coesite and amorphous SiO2 at 500 A degrees C. [GRAPHICS] .Öğe Nötral koşullarda sentezlenen polianilinin iletkenliğinin incelenmesi(Hatay Mustafa Kemal Üniversitesi, 2004) Nur, Yusuf; Çolak, NureddinÖZET NOTRAL KOŞULLARDA SENTEZLENEN POLIANILININ İLETKENLİĞİNİN İNCELENMESİ Polianilin, protonik asitlerle dop edilip iletkenliği artan nadir polimerlerdendir. Ancak sentez koşullarının asidik olması, elde edilen polianilinin kendinden dopingli olmasına neden olmaktadır. Bu nedenle doping işlemiyle protonik asitin iletkenliğe olan katkısı kesin olarak belirlenememektedir. Nötral sentez koşullarını sağlamak için, anilinin etanoldeki, amonyum persülfatın sudaki çözeltileri hazırlandı. 0 ve 25°C'lerde hazırlanan polianilin örneklerinin verimi hesaplandı. FTIR spektrumları ile karakterize edildi. Polianilin polimerlerinin Sentezlenen polianilin örnekleri toz haline getirilip, literatürde en iyi dopant olarak bahsedilen ve bir protonik asit olan HC1 ile dop edildi. HC1 doplu polianilin örneklerinin iletkenlikleri önce Hacettepe Üniversitesinde sonra Mustafa Kemal Üniversitesi Kimya Bölümünde kendi tasarımımız olan iletkenlik ölçüm aletiyle ölçüldü. 2004, 68 sayfaÖğe Synthesis of Poly(silyne-co-hydridocarbyne) for Silicon Carbide Production(Taylor & Francis Inc, 2013) Nur, Yusuf; Toppare, LeventPre-ceramic polymers have previously been shown to be polymeric precursors to silicon carbide, diamond and diamond-like carbon. Here, we report the synthesis of a pre-ceramic polymer, poly(silyne-co-hydridocarbyne), which was electrochemically synthesized from one monomer containing both silicon and carbon in its structure. The polymer is soluble in common solvents such as CHCl3, CH2Cl2 and THF. Since the polymer contains both silyne and carbyne on its backbone, it can be easily converted to silicon carbide upon heating under an ambient inert atmosphere, or to SiO2 under ambient air atmosphere. Poly(silyne-co-hydridocarbyne) was characterized with UV/Vis spectroscopy, FTIR, H-1-NMR, GPC and Raman spectroscopy. Conversion of the polymer to SiC ceramic was accomplished by heating at 1000 and 750 degrees C under an argon atmosphere and characterized with optical microscopy, SEM, X-Ray and Raman spectroscopies.Öğe Synthesis of Schiff base-containing benzoxazine derivatives(Wiley, 2019) Timur, Mahir; Nur, Yusuf; Sikar, HuseyinThe excellent chemical and physical properties of benzoxazine resins and the functionality of Schiff bases were combined in one compound's structure, creating newly designed benzoxazine derivatives that can form complexes with metals. The new type of benzoxazine monomer was synthesized via the ring-closure reaction of formaldehyde, aniline, and three newly designed Schiff bases. The presence of the Schiff base in the molecular structure of these novel benzoxazine monomers enables them to trap metals as the functional compounds, like Cu, from a solution. Thermally initiated polymerization occurs at a lower temperature by the formation of intermolecular and intramolecular hydrogen bonds between imine, oxazine, Schiff base hydroxyl groups, and the newly generated hydroxyl groups. The thermal behavior of the bisbenzoxazine monomers was investigated with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry, and then they were cured at 120, 180, and 230 degrees C. According to the magnetic susceptibility, FTIR, scanning electron microscopy with energy dispersive X-ray spectroscopy, TGA, and microwave plasma atomic emission spectroscopy results, it is shown that Cu(II) complexes of the compounds were also succesfully synthesized, and they proved to be successful in catching metal. This is due to the functionality of Schiff bases forming the metal complexation in the compounds. The poly(bisbenzoxazine)s also showed high limiting oxygen index (31-37), low ring-opening temperature (150-190 degrees C), high char yield (35%-49%), and excellent thermal stability, due to the highly crosslinked nature of the polymers. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47908.
