Bulunan: 50 Adet 0.001 sn
Koleksiyon [19]
Yayın Türü [3]
Yazar [20]
Yayın Yılı [18]
Konu Başlıkları [20]
Yayıncı [15]
Yayın Dili [1]
Dergi Adı [20]
Synthesis of PMMA-PTHF-PMMA and PMMA-PTHF-PST linear and star block copolymers

Macit, Hülya | Hazer, Baki

Article | 2004 | Journal of Applied Polymer Science93 ( 1 ) , pp.219 - 226

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly-THF)-polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF6 and bis(4,4' bromo-methyl benzoyl) peroxide (BBP) or bis (3,5,3',5' dibromom-ethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly-THF initiators with MW varying from 7,500 to 59,000 Da. Poly-THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C . . .to obtain poly(THF-b-MMA) block copolymers containing the peroxide group in the middle. Poly(MMA-b-THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA-b-PTHF-b-PMMA and PMMA-b-PTHF-PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT-IR, DSC, TGA, 1H-NMR, and 13C-NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc Daha fazlası Daha az

The synthesis of PHA-g-(PTHF-b-PMMA) multiblock/graft copolymers by combination of cationic and radical polymerization

Macit, Hülya | Hazer, Baki | Arslan, Hülya | Noda, Isao

Article | 2009 | Journal of Applied Polymer Science111 ( 5 ) , pp.2308 - 2317

A new and promising method for the diversification of microbial polyesters based on chemical modifications is introduced. Poly(3-hydroxy alkanoate)-g-(poly(tetrahydrofuran)-b-poly(methyl methacrylate)) (PHAg-(PTHF-b-PMMA)) multigraft copolymers were synthesized by the combination of cationic and free radical polymerization. PHA-g-PTHF graft copolymer was obtained by the cationic polymerization of THF initiated by the carbonium cations generated from the chlorinated PHAs, poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) in the presence of AgSbF 6. Therefore, PHA-g-PTHF gr . . .aft copolymers with hydroxyl ends were produced. In the presence of Ce +4 salt, these hydroxyl ends of the graft copolymer can initiate the redox polymerization of MMA to obtain PHA-g-(PTHF-b-PMMA) multigraft copolymer. Polymers obtained were purified by fractional precipitation. In this manner, their ?-values (volume ratio of nonsolvent to the solvent) were also determined. Their molecular weights were determined by GPC technique. The structures were elucidated using 1H-NMR and FTIR spectroscopy. Thermal analyses of the products were carried out using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2308-2317, 2009 Daha fazlası Daha az

Synthesis, characterization, and antibacterial activity of metal nanoparticles embedded into amphiphilic comb-type graft copolymers

Kalaycı, Özlem A. | Cömert, Füsun B. | Hazer, Baki | Atalay, Turgay | Cavicchi, Kevin A. | Çakmak, Mükerrem

Article | 2010 | Polymer Bulletin65 ( 3 ) , pp.215 - 226

The synthesis, spectroscopic characterization, and antimicrobial efficiency of gold and silver nanoparticles embedded in novel amphiphilic comb-type graft copolymers having good film-forming properties have been described. Amphiphilic comb-type graft copolymers were synthesized by the reaction of chlorinated polypropylene (PP) (Mw = 140,000 Da) with polyethylene glycol (PEG) (Mn = 2,000 Da) at different molar ratios. Metal nanoparticles embedded graft copolymers were prepared by reducing solutions of the salts of silver or gold and the copolymer in tetrahydrofuran. The optical properties of the metal nanoparticle embedded copolymers . . . were determined by using UV-visible spectroscopy. Surface plasmon resonance (SPR) of the gold and silver nanoparticle embedded copolymers in toluene was observed at a maximum wavelength (?max) of 428 and 551 nm in the UV-VIS absorption spectra, respectively. The average particle diameters of the gold and silver nanoparticles were found to be 50 nm from the high resolution scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Amphiphilic polymer films containing silver and gold nanoparticles were found to be highly antimicrobial by virtue of their antiseptic properties to Escherichia coli and Staphylococcus aureus. © Springer-Verlag 2009 Daha fazlası Daha az

Biomonitoring of polycyclic aromatic hydrocarbons in urban and industrial environments of the Western Black Sea Region, Turkey

Çabuk, Hasan | Kılıç, Muhammet Samet | Ören, Muhammet

Article | 2014 | Environmental Monitoring and Assessment186 ( 3 ) , pp.1515 - 1524

This research was carried out in the cities of Zonguldak and Eregli, which have been characterized as urban and industrial environments of the Western Black Sea Region, Turkey, in order to assess the contamination of polycyclic aromatic hydrocarbons (PAHs) using mosses as biomonitors. The methodology involved the collection of moss samples (Hypnum cupressiforme), ultrasonic extraction with dichloromethane, cleanup using silica gel and analysis by liquid chromatography with ultraviolet detection. The total PAH concentrations ranged from 78.1 to 1693.5 ng g -1 in Zonguldak and from 15.2 to 275.1 ng g -1 in Eregli. The total PAH concen . . .tration in Eregli was about six times lower than that in Zonguldak, revealing the importance of switching from coal to natural gas in residential heating. The diagnostic ratios and the correlation analysis have indicated that coal combustion and traffic emissions were the major PAH sources at both sites. The contour maps were constructed for the determination of spatial distributions of total PAHs, and it was shown for Zonguldak as well as for Eregli that the PAH pollution was much more predominant in highly populated regions. Moving away from the city centres, a gradual decrease in PAH pollution rates was observed. © 2013 Springer Science+Business Media Daha fazlası Daha az

Synthesis of segmented polyurethane based on polymeric soybean oil polyol and poly (ethylene glycol)

Keleş, Elif | Hazer, Baki

Article | 2009 | Journal of Polymers and the Environment17 ( 3 ) , pp.153 - 158

Polyurethane (PUR) plastic sheets were prepared by reacting hydroxylated polymeric soybean oil (PSbOH) synthesized from autoxidized soybean oil with polyethylene glycol (PEG) in the presence of isophorone diisocyanate (IPDI). FTIR technique was used to identify of chemical reactions. These polyurethanes have different valuable properties, determined by their chemical composition. The effect of stoichiometric balance (i.e., PSbOH/PEG-2000/IPDI weight ratio) on the final properties was evaluated. The polyurethane plastic sheets with the PSbOH/PEG-2000/IPDI weight ratio 1.0/1.0/0.67 and 1.0/0.3/0.3 had excellent mechanical properties i . . .ndicating elongation at break more than 200%. Increase in IPDI and decrease in PEG weight ratio cause the higher stress-strain value. The properties of the materials were measured by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), stress-strain measurements and FTIR technique. © 2009 Springer Science+Business Media, LLC Daha fazlası Daha az

Synthesis of Polylactide-b-Poly (Dimethyl Siloxane) Block Copolymers and Their Blends with Pure Polylactide

Hazer, Baki | Baysal, Bahattin M. | Köseoğlu, Ayşe G. | Beşirli, Necati | Taşkın, Elif

Article | 2012 | Journal of Polymers and the Environment20 ( 2 ) , pp.477 - 484

The synthesis of polylactide (PLA)-b-poly (dimethyl siloxane) (PDMS) linear block copolymers and their use in blends with pure-PLA are described. PLA-b-PDMS linear block copolymers were obtained by the transesterification reaction in chloroform solution between poly(dimethyl siloxane) bis (2-aminopropyl ether) (molecular weight 2,000 Da) with PLA in the presence of stannous octoate. Molecular weights (Mw) of the block copolymers were varied from 53,800 to 63,600 Da while that of pristine PLA was 73,600 Da. The copolymers obtained were purified by fractional precipitation and then characterized by 1 H NMR, FTIR, GPC, viscometry and D . . .SC techniques. Blends of pure PLA with PLA-b-PDMS block copolymers displayed improved elastic properties (elongation up to 140%) compared to pure PLA (elongation ~9%). Thermal, mechanical and morphological characterization of the blends were also conducted. © 2011 Springer Science+Business Media, LLC Daha fazlası Daha az

Synthesis and characterization of the novel thermoresponsive conjugates based on Poly(3-hydroxy alkanoates)

Toraman, Tuğba | Hazer, Baki

Article | 2014 | Journal of Polymers and the Environment22 ( 2 ) , pp.159 - 166

Novel thermoresponsive polymer conjugates based on microbial polyesters and poly-N-isopropyl acryl amide, PNIPAM, have been reported. The unsaturated poly-3-hydroxy alkanoates, poly (3-hydroxy undecenoate), PHU, and 1:1 mixture of 10-undecenoic acid and soy oil acids, PHU-Sy, were brominated by using bromine in the dark, at room temperature. Brominated PHAs were transformed to macro reversible addition-fragmentation chain transfer (RAFT) agents via the substitution reaction with potassium ethyl xanthate. RAFT polymerization of N-isopropyl acryl amide, NIPAM, was initiated by the PHA-derivative containing xanthate pendant groups in o . . .rder to obtain brush type PHA-g-PNIPAM thermo responsive amphiphilic graft copolymers. The water uptake of the PHU-g-PNIPAM and PHU-Sy-g-PNIPAM amphiphilic graft copolymers changed from 50 % to completely soluble in water. Structural and thermal characterization of the novel conjugates were carried out by using 1H NMR, GPC, DSC and TGA techniques. Graphical Abstract: [Figure not available: see fulltext.] © 2014 Springer Science+Business Media New York Daha fazlası Daha az

Synthesis and characterization of poly(N-isopropyl acryl amide)-g-poly(LINOLEIC ACID)/poly(linolenic acid) graft copolymers

Allı, Abdulkadir | Hazer, Baki

Article | 2011 | JAOCS, Journal of the American Oil Chemists' Society88 ( 2 ) , pp.255 - 263

To diversify edible oil thermoresponsive polymer composites, polymeric linoleic acid peroxide (PLina) and polymeric linolenic acid peroxide (PLinl) were obtained by the autoxidation of linoleic acid (Lina) and linolenic acid (Linl), respectively. The autoxidation of Lina and Linl under air at room temperature rendered waxy soluble polymeric peroxide, having a soluble fraction in chloroform of more than 91 wt% and containing up to 1.0 wt% of peroxide. The soluble polymeric oil macro-peroxide was used to initiate the free radical polymerization of N-isopropylacrylamide, NIPAM, resulting in PLina-g-PNIPAM and PLinl-g-PNIPAM graft copol . . .ymers, respectively. The PNIPAM content of the graft copolymers was calculated using the elemental nitrogen analysis of graft copolymers. Thermal analysis, FTIR, 1H NMR, and SEM techniques were used in the characterization of the products. The hydrophobic effect of the fatty acid macro peroxides on the thermal response rate of the graft copolymers was investigated by means of swelling-deswelling behaviors in response to temperature change. They have a thermoresponsive character and exhibit a volume phase transition at approximately 27-30 °C, which is 1-4 °C lower than that of pure PNIPAM. A plastizer effect of PLina and PLinl in graft copolymers was observed, indicating a lower glass transition temperature than that of pure PNIPAM. © 2010 AOCS Daha fazlası Daha az

Synthesis and characterization of polymeric soybean oil-g-methyl methacrylate (and n-butyl methacrylate) graft copolymers: Biocompatibility and bacterial adhesion

Çakmaklı, Birten | Hazer, Baki | Tekin, İshak Özel | Cömert-Beğendik, Füsun

Article | 2005 | Biomacromolecules6 ( 3 ) , pp.1750 - 1758

Peroxidation, epoxidation, and/or perepoxidation reactions of soybean oil under air at room temperature resulted in cross-linked polymeric soybean oil peroxides on the surface along with the waxy soluble part, sPSB, with a molecular weight of 4690, containing up to 2.3 wt % peroxide. This soluble polymeric oil peroxide, sPSB, initiated the free radical polymerization of either methyl methacrylate (MMA) or n-butyl methacrylate (nBMA) to give PSB-g-PMMA and PSB-g-PnBMA graft copolymers. The polymers obtained were characterized by 1H NMR, thermogravimetric analysis, differential scanning calorimetry, and gel permeation chromatography t . . .echniques. Polymeric oil as a plasticizer lowered the glass transition of the PSB-g-PMMA graft copolymers. PSB-g-PMMA and PSB-g-PnBMA graft copolymer film samples were also used in cell culture studies. Fibroblast and macrophage cells were strongly adhered and spread on the copolymer film surfaces, which is important in tissue engineering. Bacterial adhesion on PSB-g-PMMA graft copolymer was also studied. Both Staphylococcus epidermidis and Escherichia coli adhered on the graft copolymer better than on homo-PMMA. Furthermore, the latter adhered much better than the former. © 2005 American Chemical Society Daha fazlası Daha az

Tailoring polymer architectures with macromonomer azoinitiators

Yıldız, Ufuk | Hazer, Baki | Tauer, Klaus

Review | 2012 | Polymer Chemistry3 ( 5 ) , pp.1107 - 1118

The synthesis and characterization of novel quinone-amine polymers from the reactions of 2,3-dichloro-1,4-naphthoquinone and polyoxypropylenediamines

Ayla-Şahinler, Ayla | Bahar, Hakan | Yavuz, Şenol | Hazer, Baki | İbiş, Cemil

Article | 2016 | Phosphorus, Sulfur and Silicon and the Related Elements191 ( 3 ) , pp.438 - 443

A series of novel N-and N,N'-bis(quinonyl)amines were synthesized from the reactions of 2,3-dichloro-1,4-naphthoquinone (1) and polyoxypropylenediamines. The novel quinone-amine polymers were treated with some thiols in next step and N,S-substituted compounds were obtained. The structures of the novel products were characterized by micro-analysis, 1H NMR, UV-VIS, 13C NMR, and MS. The electrochemical properties of some of the novel amine-quinone polymers derivatives were also investigated by cyclic voltammetry. The number of molecular weight (Mn) of polymer compounds was also determined by Gel Permeation Chromatography (GPC). © 2016 . . .Taylor & Francis Group, LLC Daha fazlası Daha az

Synthesis of a new macroperoxy initiator with methyl methacrylate and t-butyl peroxy ester by atom transfer radical polymerization and copolymerization with conventional vinyl monomers

Öztürk, Temel | Yılmaz-Savaşkan, Sevil | Hazer, Baki

Article | 2008 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry45 ( 10 ) , pp.811 - 820

In this study, we present the synthesis of poly-MMA macroperoxy initiators obtained by the ATRP of MMA with bromo methyl benzyl t-butyl peroxy ester (t-BuBP) as an initiator, and CuX (X:Br or Cl)/2,2'-bipyridine (bpy) as a catalyst system at 0, 20, 30 and 40C. The peroxygen groups do not decompose during the ATRP reaction, because low reaction temperatures used for the ATRP reaction are not enough to decompose them. The peroxygen groups of poly-PMMA macroperoxy initiators can lead them to react with a monomer by using appropriate reaction conditions to obtain the block or graft copolymers. For this purpose, poly-MMA macroperoxy init . . .iators were used to synthesize poly(MMA-b-S) block copolymers with S and used for graft copolymerization of polybutadiene (PBd) and natural rubber (RSS-3) to obtain crosslinked poly(MMA-g-PBd) and poly(MMA-g-RSS-3) graft copolymers. Swelling ratio values of the crosslinked graft copolymers in CHCl3 were calculated. The characterizations of the polymers were achieved by FT-IR, 1H-NMR, GPC, DSC, SEM, and the fractional precipitation () techniques. The reaction schemes were also performed using the HYPERCHEM 7.5 program. The mechanical properties of the products were investigated Daha fazlası Daha az

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