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Öğe An-easy-to-build rotational viscometer with digital readout(Amer Chemical Soc, 1996) Seckin, T; Kormali, SM[Abstract Not Available]Öğe Polyimides from a novel monomer 3,6-bis(dimethylamino) acridine(p-cymene)dichlororuthenium(II) for a catalytic application(Springer, 2004) Seckin, T; Koytepe, S; Özdemir, I; Gürbüz, N; Çetinkaya, BTricyclic heteroaraomatic dye-based monomer containing NMe2 units, 6-bis(dimethylamino)acridine(p-cymene)dichlororuthenium (II), was used to prepare novel polyimides via a one-stage solution polycondensation due to their stability under a variety of oxidative and reductive conditions. The Ru(II) complex monomer was synthesized starting from [RuCl2(p-cymene)](2) and 3,6-bis(dimethylamino)acridine. A series of stable polyimides was synthesized from the Ru(II) complex of 3,6-bis(dimethylamino)acridine and various aromatic dianhyrides. The polymers had inherent viscosities ranging from 1.72 to 2.11 dL/g and were soluble in polar solvents. The glass transition temperatures were 192-278degreesC, and the 10% weight loss temperatures were above 503-635degreesC. Ruthenium-substituted polyimides were tested for catalytic activity in the furan formation reaction of (Z)-3-methylpent-2-en-4-yn-1-ol. The polymeric catalyst was added to (Z)-3-methylpent-2-en-4-yn-1-ol without a solvent and the pure furan was isolated by distillation under reduced pressure. The conversion of the starting, enynol, was determined by gas chromatography (GC).Öğe Preparation and characterization of a clay-polyvinylpyridinium matrix for the removal of bacterial cells from water(Chapman Hall Ltd, 1997) Seckin, T; Onal, Y; Yesilada, O; Gultek, APolyvinylpyridinium salts were immobilized onto a clay matrix and were then tested for their antibacterial properties. The clay-polyvinylpyridinium matrix was prepared by the copolymerization of gamma-methacryloxypropyltriethoxy silane bonded covalently to clay and 4-vinylpyridine and subsequent quaternization with benzyl halides. Suspension tests for antibacterial properties of the immobilized bactericide against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa demonstrated the high activity of the pyridinium salts that are bonded to the polyacrylate spacer. Advantageously, these insoluble clay-polymer bactericides could be applied without any contamination by the substrate.Öğe Preparation and characterization of novel polyimides from 2,6-bis[1-(p-dimethylaminophenylimino)ethyl] pyridine for the selective extraction of some metals(Springer, 2005) Seckin, T; Köytepe, SA group of new polyimides has been prepared by solution condensation of 2,6-bis[1-(p-dimethylaminophenylimino)ethyl] pyridine containing pendant NMe2 units and various dianhyrides in N-methylpyrrolidone (NMP). The tridentate (N-N'-N) pydim ligands were prepared by Schiff-base condensation of 2,6-diacetylpyridine and 4-dimethylaminoaniline in the presence of formic acid as catalyst. These polymers were investigated for their extraction capabilities for Zn(II), Mn(II), Cu(II), Cd (II) and Ni(II) and at different pH. Under different conditions enhanced selectivity was observed. Up to 98% quantitative recoveries were observed for all metals.Öğe Preparation and phenol captivating properties of polyvinylpyrrolidone-montmorillonite hybrid materials(Wiley, 2001) Gultek, A; Seckin, T; Onal, Y; Icduygu, MGMontmorillonite minerals were modified in two distinct steps in order to remove hydroxlated toxicants from the aqueous environment. At first, the montmorillonite minerals were acrylated with the silylating agent gamma -methcaryloxypropyl trimethoxysilane to give a product denoted as TAY-10. In the second step these materials readily reacted with vinylpyrrolidone to form copolymers covalently bonded to the clay. All hybrid materials were characterized by FTIR spectroscopy, thermogravimetry, X-ray diffractometry, SEM, and differential thermal analysis. The original montmorillonite structure was maintained for the copolymer modified surfaces. Different loadings of polyvinylpyrrolidone (PVP) were examined to arrive at the optimal conditions for the removal of toxicants from the aqueous environment. The presence of the PVP enhanced the adsorption capacity of the clay toward phenolic compounds from solution as evidenced by the retention percent that was as high as 98.9%. These results demonstrated the feasibility of utilizing a PVP modified clay as a thermally recyclable adsorbent for environmental pollutants. (C) 2001 John Wiley & Sons, Inc.Öğe Syntheses and properties of metal containing polyimides based on the gold carbene complex(Springer, 2003) Seckin, T; Koytepe, S; Ozdemir, I; Çetinkaya, BA novel gold carbene complex, bis(1,3-di-p-dimethylaminobenzylimidazolidinylidene) gold(I), was synthesized and polymerized to polyimides in a one-step method with various aromatic dianhyrides. The gold-coordinated polyimides are characterized by IR and NMR (H-1, C-13) spectroscopy. The materials have inherent viscosities that range from 1.88 to 2.39 dl/g and show excellent solubility in N-methylpyrrolidone and N,N-dimethylacetamide. The glass transition temperatures of the coordinated polyimides range from 203-265degreesC and a 5% weight loss in air is observed from 535-578degreesC. The polymers form dark yellow, tough films that are transparent above 365 nm. The effect of different flexible units on the properties of the polyimides is discussed.Öğe Synthesis and catalytic properties of arene complexes of ruthenium(II) prepared from Si, Zr, Ti and Al alkoxides by the sol-gel process(Royal Soc Chemistry, 1998) Cetinkaya, B; Seckin, T; Ozdemir, I; Alici, BMethods of synthesizing materials for catalysis were developed by synthesizing eta-arene complexes of ruthenium(II) coordinated to vinylpyridine that was followed by sol-gel polymerization with 3-methacryloxypropyltriethoxysilane. To enforce sufficient catalytic properties, a series of hybrid materials from Si, Zr, Ti and Al alkoxides were prepared by co-condensation. The hydrolysis and polycondensation of materials were performed at different experimental conditions. The monomeric compounds were identified and catalytic activities were tested for cyclization of (Z)-3-methylpent-2-en-4-yn-1-ol to 2,3-dimethylfuran.Öğe Synthesis and characterization of N-substituted 1,4,5,6-tetrahydropyrimidine containing functional polymers as SO2 and CO2 sorbents(John Wiley & Sons Inc, 1997) Seckin, T; Alici, B; Cetinkaya, E; Ozdemir, INovel vinyl monomers containing 1,4,5,6-tetrahydropyrimidine were prepared by the reaction of N-substituted-1,3-diaminopropane with N,N-dimethyl-formamide dimethylacetal, which gave l-alkyl or aryl substituted 1,4,5,6-tetrahydropyrimidines, Alkylation of the tetrahydropyrimidine derivatives by chloromethylstyrene produces the N-methyl-N'-vinyl benzyl-1,4,5,6-tetrahydropyrimidinium chloride in high yields, These monomers were readily polymerized in dimethylformamide by AIBN at 80 degrees C. Homopolymers and soluble linear copolymers were prepared and copolymerization parameters were rationalized. Further, insoluble terpolymers prepared from these monomers, styrene and divinylbenzene were tested for the sorption of the weakly acidic gases gave excellent results. (C) 1997 John Wiley & Sons, Inc.Öğe Synthesis and characterization of novel polyacrylate-clay sol-gel materials(Chapman Hall Ltd, 1996) Seckin, T; Onal, Y; Aksoy, I; Yakinci, MEOrgano-functional silanes which were able to form chemical bonds with kaolinite and could also have an affinity to the materials of concern here, were studied by the sol-gel process. Polymethacrylate with trialkoxy silyl functional groups were prepared, hydrolysed and co-condensed with kaolinite. The progress of the hydrolysis, which proceeded very slowly, was followed by Karl-Fischer titration. Thermal behavior was investigated by differential thermal analysis. The extent of the reaction leading to network formation was qualitatively followed by Fourier transform-infrared spectroscopy and X-ray diffraction. Free-radical polymerization was carried out ultrasonically in the presence of a catalyst. Trimethoxy silane end-capped silane was found to be covalently bonded to kaolinite. The copolymers, with various amounts of kaolinite, were then hydrolysed and co-condensed in the presence of a catalyst to yield sol-gel materials which have a controllable combination of properties of both the polymer and kaolinite.Öğe Synthesis and properties of novel polyimides from dichloro (1,3-p-dimethylaminobenzylimidazolidine-2-ylidene) p-cymene ruthenium (II)(Taylor & Francis Ltd, 2003) Seckin, T; Köytepe, S; Çetinkaya, B; Özdemir, I; Yigit, BA novel diamine derivative, dichloro (1,3-p-dimethylaminobenzylimidazolidine-2-ylidene) p-cymene ruthenium (11), bearing a potential site for imide formation, was prepared starting from p-dimethylaminobenzaldehyde. It was used as a monomer to prepare polyimides with several dianhydrides via a one-stage procedure without going through tedious steps. The polyimides have inherent viscosities that range from 1.18 to 1.24 dl/g in N-methyl-2-pyrrolidinone at 30degreesC. These new polymers are soluble in polar aprotic solvents. The polymeric catalyst was added to (Z)-3-methylpent-2-en-4-yn-1-ol without a solvent and the pure furan was isolated by distillation under reduced pressure and GC determined the conversion of the starting enynol.Öğe Synthesis and properties of polyimides from 1,3-di(p-dimethylaminobenzyl)-imidazolidine-2-thion(Springer, 2003) Seckin, T; Çetinkaya, E; Köytepe, S; Yigit, BA synthetic strategy is presented that allows the preparation of dimethylamino functionalized. heterocyclic system 1,3-di (p-dimethylaminobenzyl)-imidazolidine-2-thion that was then used to prepare polyimides by the two-stage polycondensation method. The key to this success was the development of an efficient procedure leading highly pure dimethylamino monomer. Polyimides derived from 1,3-di(p-dimethylaminobenzyl)-inmidazolidine-2-thion and commercial dianhydrides exhibited excellent solubility in various polar solvents. These polymers showed glass transition temperatures between 290-360degreesC, and initial decomposition temperature 490-485 degreesC and 10% mass loss ranging from 505-575degreesC in air.Öğe Synthesis and radical polymerization of novel vinyl monomers having the imidazoline and pyrimidine moiety(Springer Verlag, 1996) Seckin, T; Alici, R; Cetinkaya, E; Ozdemir, IAlkylation of the methylene bridged tetrahydropyrimidine derivatives by chloromethylstyrene produces the bridged bis(4-vinylbenzyl)-1,4,5,6,-tetrahydropyrimidinium salts in high yields. Similar procedures are used to prepare 2-imidazolinium derivatives. The quaternary salts which support functional side groups of potential biomedical interest are characterized by means of spectroscopic methods. These monomers are readily polymerized free radically in solution of dimethyl formamide at moderate temperatures. The soluble and insoluble polymers containing 2-imidazolinium and 1,4,5,6-tetrahydropyrimidinium salts were found to exhibit antibacterial activites against Escherichia coli.Öğe Synthesis, characterization and thermal properties of bentonite-polyacrylate sol-gel materials(Royal Soc Chemistry, 1997) Seckin, T; Gultek, A; Onal, Y; Yakinci, ME; Aksoy, IA new type of material incorporating bentonite with an alkoxide, H2C=C(CH3)COO(CH2)(3)Si(OCH3)(3), has been prepared successfully using a sol-gel process. The structures and structural changes upon heating, of the bentonite and the sol-gel material. were investigated by FTIR, XRD and DSC. Using the metal alkoxide and the corresponding clay mineral as precursors, the additive reaction followed by free radical polymerization resulted in a novel material in which polymer was attached covalently to, silicate sheets of bentonite via hydroxy bonding.
