Filtreler
Filtreler
Bulunan: 12 Adet 0.001 sn
Koleksiyon [7]
Tam Metin [2]
Yayın Türü [1]
Yazar [14]
Yayın Yılı [8]
Konu Başlıkları [20]
Yayıncı [4]
Yayın Dili [1]
Dergi Adı [6]
Synthesis and characterization of poly(Ɛ-caprolactone-co-ethylene glycol) star-type amphiphilic copolymers by “click” chemistry and ring-opening polymerization.

Öztürk, Temel | Kılıçlıoğlu, Ali | Savaş, Bedrettin | Hazer, Baki

Article | 2018 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry55 ( 8 ) , pp.588 - 594

The synthesis of poly(?-caprolactone-co-ethylene glycol) AAB star-type amphiphilic copolymers were carried out by use of a “click” chemistry reaction to block propargyl polyethylene glycol (propargyl-PEG) to terminally azide poly(?-caprolactone) (PCL-N3). For this purpose, propargyl-PEG was synthesized by the reaction of PEGs (3000 Da, 2000 Da, 1500 Da, and 1000 Da) and propargyl chloride. Terminally chloride poly(?-caprolactone) (PCL-Cl) was carried out by means of ring-opening polymerization (ROP) of ?-caprolactone (CL) and 3-chloro-1,2-propanediol. Synthesis of PCL-N3 was obtained by the chemical interaction of PCL-Cl and sodium . . .azide. By reacting propargyl-PEG and PCL-N3, the star-type amphiphilic copolymers were obtained. The characterization of products was accomplished by using multiple instruments including 1H-NMR, FT-IR, GPC, TGA, contact angles, and elemental analysis techniques. © 2018, © 2018 Taylor & Francis Group, LLC Daha fazlası Daha az

Synthesis and characterization of a novel macromonomer initiator for reversible addition fragmentation chain transfer (RAFT). Evaluation of the polymerization kinetics and gelation behaviors

Öztürk, Temel | Hazer, Baki

Article | 2010 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry47 ( 3 ) , pp.265 - 272

Reversible addition fragmentation chain transfer, RAFT, self condensing a novel macromonomer initiator polymerization and copolymerization with methyl methacrylate, MMA, in the presence of 2,2' -azobisisobutyronitrile, AIBN, has been reported. RAFT-MIM was obtained from potassium salt of the ethyl xanthegonate and the terminally brominated poly (ethylene glycol) methacrylate (v-PEG-Br) which was synthesized by the reaction of poly (ethylene glycol) methacrylate, v-PEG-OH with Mn = 526 Dalton and 3-bromopropionyl chloride. Self condensing RAFT-MIM polymerization and copolymerization with MMA gave highly branched and cross-linked amph . . .iphilic copolymers. The kinetic parameters were evaluated by changing some polymerization conditions such as monomer, initiator and solvent concentration, polymerization time and polymerization temperature. The plots of ln (M0/M) versus reaction time are linear, corresponding to first-order kinetics. The overall polymerization rate constant, k, was calculated as 7.9 10-5 s-1. The products were characterized by 1H-NMR and TGA. Swelling ratio values of the crosslinked products in CHCl3 were also determined Daha fazlası Daha az

Synthesis of pH- and thermo-responsive poly (ε-caprolactone-b-4-vinyl benzyl-g-dimethyl amino ethyl methacrylate) brush type graft copolymers via RAFT polymerization

Şanal, Timur | Oruç, Olgu | Öztürk, Temel | Hazer, Baki

Article | 2015 | JOURNAL OF POLYMER RESEARCH22 ( 2 ) , pp.265 - 272

A novel pH-and thermo-responsive poly (epsilon-caprolactone-b-4-vinyl benzyl-g-2-(dimethyl amino ethyl) methacrylate), poly (CL-b-VB-g-DMAEMA), brush type copolymer has been described. In this study, a reversible addition-fragmentation chain transfer (RAFT) agent, 1,2-propanediol- 3-ethyl xanthogenate, was obtained through the reaction of 3-chloro-1,2-propanediol with potassium salt of ethyl xanthogenate. Poly (CL-b-VB) block copolymer was synthesized in one-pot polymerization of e-caprolactone (CL) and 4-vinyl benzyl chloride (VB) using a new dual macro-RAFT agent. In the second step of the work, chloride side groups of poly-VB in . . .poly (CL-b-VB) block copolymer were reacted with potassium salt of ethyl xanthogenate to obtain another novel macro-RAFT agent, poly (CL-b-VB)-g-xanthate (PCL-PVB-Xa). Controlled free radical living polymerization of 2-(dimethylaminoethyl) methacrylate (DMAEMA) was initiated with this PCL-VB-Xa macro-RAFT agent to obtain new poly (CL-b-VB-g-DMAEMA) comb type pH-and thermo-responsive heterograft copolymer. The homopolymer was soluble in water at pH=10-11 and not soluble at pH=12.5. A pH-sensitive feature of the brush type graft copolymer was observed between pH9.4 and 11.5 in view of their swelling/solution properties depending on the acrylic polymer inclusion. The LCST values of the multiblock brush type copolymers were found to be as low as 42.8 degrees C, while that of PDMAEMA homopolymer was 46.6 degrees C. The characterization of the products was achieved using gel-permeation chromatography (GPC), thermal, and spectrometric analysis techniques. pH- and thermo-responsiveness of the copolymers were verified by surface tension and zeta potential measurements Daha fazlası Daha az

Synthesis and characterization of poly(vinyl chloride-graft-2- vinylpyridine) graft copolymers using a novel macroinitiator by reversible addition-fragmentation chain transfer polymerization

Öztürk, Temel | Göktaş, Melahat | Savaş, Bedrettin | Işıklar, Mustafa | Atalar, Mehmet Nuri | Hazer, Baki

Article | 2014 | E-Polymers14 ( 1 ) , pp.27 - 34

Synthesis of poly(vinyl chloride-graft-2-vinylpyridine) graft copolymers was carried out by reversible addition-fragmentation chain transfer (RAFT) polymerization of 2-vinylpyridine using a novel macroinitiator (RAFT macroinitiator). For this purpose, RAFT macroinitiator was obtained from the potassium salt of ethyl xanthogenate and poly(vinyl chloride) (PVC). Then the graft copolymers were synthesized by using RAFT macroinitiator and 2-vinylpyridine. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the polymerization reaction were studied. The effect of the reactio . . .n conditions on the heterogeneity index and molecular weight was also investigated. The block lengths of the graft copolymers were calculated by using 1H nuclear magnetic resonance (1H NMR) spectra. The block lengths of the copolymers could be adjusted by varying the monomer and initiator concentrations. The characterizations of the samples were carried out by using 1H NMR, Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, and fractional precipitation (? value) techniques. RAFT polymerization is used to control the polymerization of 2-vinylpyridine over a broad range of molecular weights Daha fazlası Daha az

Synthesis and characterization of graft copolymers based on polyepichlorohydrin via reversible addition-fragmentation chain transfer polymerization

Öztürk, Temel | Kayğın, Oğuz | Göktaş, Melahat | Hazer, Baki

Article | 2016 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry53 ( 6 ) , pp.362 - 367

In this study, synthesis of poly(epichlorohydrin-g-methyl methacrylate) graft copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization was reported. For this purpose, epichlorohydrin was polymerized by using HNO3 via cationic ring-opening mechanism. A RAFT macroinitiator (macro-RAFT agent) was obtained by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin. The graft copolymers were synthesized using macro-RAFT agent as initiator and methyl methacrylate as monomer. The synthesis of graft copolymers was conducted by changing the time of polymerization and the amount of monomer-initiator co . . .ncentration that affect the RAFT polymerization. The effects of these parameters on polymerization were evaluated via various analyses. The characterization of the products was determined using 1H-nuclear magnetic resonance (1H-NMR), Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, elemental analysis, and fractional precipitation techniques. The block lengths of the graft copolymers were calculated by using 1H-NMR spectrum. It was observed that the block length could be altered by varying the monomer and initiator concentrations. © 2016 Taylor & Francis Group, LLC Daha fazlası Daha az

One-step synthesis of block-graft copolymers via simultaneous reversible-addition fragmentation chain transfer and ring-opening polymerization using a novel macroinitiator

Öztürk, Temel | Atalar, Mehmet Nuri | Göktaş, Melahat | Hazer, Baki

Article | 2013 | Journal of Polymer Science, Part A: Polymer Chemistry51 ( 12 ) , pp.2651 - 2659

One-step synthesis of block-graft copolymers by reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) by using a novel initiator was reported. Block-graft copolymers were synthesized in one-step by simultaneous RAFT polymerization of n-butylmethacrylate (nBMA) and ROP of ?-caprolacton (CL) in the presence of a novel macroinitiator (RAFT-ROP agent). For this purpose, first epichlorohydrin (EPCH) was polymerized by using H2SO4 via cationic ring-opening mechanism. And then a novel RAFT-ROP agent was synthesized by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin (poly-EPCH). B . . .y using the RAFT-ROP agent, poly[CL-b-EPCH-b-CL-(g-nBMA)] block-graft copolymers were synthesized. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one-step polymerization reaction were evaluated. The block lengths of the block-graft copolymers were calculated by using 1H-nuclear magnetic resonance (1H NMR) spectrum. The block length could be adjusted by varying the monomer and initiator concentrations. The characterization of the products was achieved using 1H NMR, Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, elemental analysis, and fractional precipitation (?) techniques. © 2013 Wiley Periodicals, Inc 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

ATRP of methyl methacrylate initiated with a bifunctional initiator bearing bromomethyl functional groups: Synthesis of the block and graft copolymers

Öztürk, Temel | Yılmaz-Savaşkan, Sevil | Hazer, Baki | Menceloğlu, Yusuf Z.

Article | 2010 | Journal of Polymer Science, Part A: Polymer Chemistry48 ( 6 ) , pp.1364 - 1373

This article reports the synthesis of the block and graft copolymers using peroxygen-containing poly(methyl methacrylate) (poly-MMA) as a macroinitiator that was prepared from the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in the presence of bls(4,4'-bromomethyl benzoyl peroxide) (BBP). The effects of reaction temperatures on the ATRP system were studied in detail. Kinetic studies were carried out to investigate controlled ATRP for BBP/CuBr/bpy initiating system with MMA at 40 °C and free radical polymerization of styrene (S) at 80 °C The plots of In ([M o]/[Mt]) versus reaction time are linear, corresp . . .onding to first-order kinetics. Poly-MMA initiators were used In the bulk polymerization of S to obtain poly (MMA-b-S) block copolymers. Poly-MMA initiators containing undecomposed peroygen groups were used for the graft copolymerization of polybutadiene (PBd) and natural rubber (RSS-3) to obtain crosslinked poly (MMA-g-PBd) and poly(MMAg-RSS-3) graft copolymers. Swelling ratio values (q v) of the graft copolymers in CHCl3 were calculated. The characterizations of the polymers were achieved by Fourier-transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance (1H NMR), gelpermeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and the fractional precipitation (?) techniques. © 2010 Wiley Periodicals, Inc Daha fazlası Daha az

Synthesis and characterization of poly(methyl methacrylate-block-ethylene glycol-block-methyl methacrylate) block copolymers by reversible addition-fragmentation chain transfer polymerization

Öztürk, Temel | Göktaş, Melahat | Hazer, Baki

Article | 2011 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry48 ( 1 ) , pp.65 - 72

Synthesis of poly(methyl methacrylate-block-ethylene glycol-block-methyl methacrylate) triblock copolymers by reversible addition-fragmentation chain transfer (RAFT) by using a novel dual macro initiator (RAFT-agent) is reported. RAFT-agent is obtained from potassium salt of the ethyl xanthegonate and the terminally brominated poly(ethylene glycol) (Br-PEG-Br) which is synthesized by the reaction of poly(ethylene glycol) [PEG] with Mn= 3000 Dalton and 3-bromopropionyl chloride. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the polymerization reaction are evaluate . . .d. The characterization of the products is achieved using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), gel-permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation () techniques. Molecular weights of the polymers obtained from GPC agreed with the theoretical values. RAFT polymerization is used to control the polymerization of MMA over a broad range of molecular weights. Copyright © Taylor & Francis Group, LLC Daha fazlası Daha az

One-step synthesis of triarm block copolymers via simultaneous reversible-addition fragmentation chain transfer and ring-opening polymerization

Öztürk, Temel | Göktaş, Melahat | Hazer, Baki

Article | 2010 | Journal of Applied Polymer Science117 ( 3 ) , pp.1638 - 1645

One-step synthesis of star copolymers by reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) by using a novel dual initiator is reported. Triarm block copolymers comprising one polystyrene (or polyacrylamide) arm and two poly(b-butyrolactone) arms were synthesized in one-step by simultaneous RAFT polymerization of styrene (St) (or acrylamide, designated as AAm) and ROP of b-butyrolactone (BL) in the presence of a novel trifunctional initiator, 1,2-propanediol ethyl xanthogenate (RAFT-ROP agent). This dual initiator was obtained through the reaction of 3-chloro-1,2- propanediol with the potas . . .sium salt of ethyl xanthogenate. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one-step polymerization reaction were evaluated. The characterization of the products was achieved using Fourier-transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance (1HNMR),13C-nuclear magnetic resonance ( 13C-NMR), Gas chromatography-mass spectrometry (GC-MS), gel-permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (c) techniques. VC 2010 Wiley Periodicals, Inc Daha fazlası Daha az

One-step synthesis of triarm block copolymers by simultaneous atom transfer radical and ring-opening polymerization

Öztürk, Temel | Yavuz, Mahmut | Göktaş, Melahat | Hazer, Baki

Article | 2016 | Polymer Bulletin73 ( 6 ) , pp.1497 - 1513

One-step synthesis of poly(MMA-b-CL) triarm block copolymers was carried out by atom transfer radical polymerization of methyl methacrylate (MMA) and ring-opening polymerization of ?-caprolactone (CL) using 3-chloro-1,2-propanediol trifunctional initiator. The triarm block copolymers comprising one poly-MMA arm and two poly-CL arms were synthesized by changing some polymerization conditions such as monomer/initiator concentration, polymerization time. The effect of the reactions conditions on the polydispersity and molecular weights was also investigated. The block lengths of the block copolymers were calculated by using 1H-nuclear . . .magnetic resonance (1H-NMR) spectrum. It was observed that the block length could be altered by varying the monomer and initiator concentrations. The characterization of the products was achieved by using 1H-NMR, Fourier-transform infrared spectroscopy, gel-permeation chromatography, differential scanning calorimetry, thermogravimetric analysis and fractional precipitation techniques. © 2015, Springer-Verlag Berlin Heidelberg Daha fazlası Daha az

One-step synthesis of triblock copolymers via simultaneous reversible-addition fragmentation chain transfer (RAFT) and ring-opening polymerization using a novel difunctional macro-RAFT agent based on polyethylene glycol

Göktaş, Melahat | Öztürk, Temel | Atalar, Mehmet Nuri | Tekeş, Ahmet T. | Hazer, Baki

Article | 2014 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry51 ( 11 ) , pp.854 - 863

One-step synthesis of the triblock copolymers was carried out by reversible addition-fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) and ring-opening polymerization (ROP) of ß-butyrolactone (BL) or ?-caprolactone (CL) using a novel difunctional macro-RAFT agent. For this purpose, primarily PEG-Br (polyethylene glycol bromine) was obtained by using 3-bromopropanoyl chloride and PEGs (polyethylene glycols) with different molecular weights. Then, macro-RAFT agent was synthesized by the reaction of potassium ethyl xanthogenate and PEG-Br. By using macro-RAFT agent, poly(MMA-b-EG-b-BL), and poly(MMA-b-EG-b . . .-CL) triblock copolymers were synthesized by changing some polymerization conditions such as monomer/initiator concentration, polymerization time. The effect of the reaction conditions on the polydispersity and molecular weights were also investigated. The block lengths of the triblock copolymers were calculated by using 1H-nuclear magnetic resonance (1H-NMR) spectra. It was observed that the block length could be altered by varying the monomer and initiator concentrations. The characterization of the products were achieved using 1H-NMR, Fourier-transform infrared spectroscopy (FTIR), gel-permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (?) techniques. © 2014 Taylor & Francis Group, LLC Daha fazlası Daha az

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