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

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

Taşkın, Elif | Hazer, Baki | Beşirli, Necati | Çavuş, Gökhan

Article | 2012 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry49 ( 2 ) , pp.164 - 170

The synthesis of polylactide (PLA)-b-polyethylene glycol (PEG) linear block copolymers and their use in blends with pure-PLA is described. PLA-b-PEG linear block copolymers were obtained by the reaction between poly(ethylene glycol) bis (2-aminopropyl ether) (molecular weight 2000 Dalton) with PLA in the presence of stannous octoate via trans esterification. Molecular weight measurements of the block copolymers indicated that AB and ABA type block copolymers were obtained by controlling the feed ratio in the trans esterification reactions. The copolymers obtained were purified by the fractional precipitation and then characterized b . . .y 1H-NMR, FTIR, GPC and DSC techniques. Blends of pure PLA with PLA-b-PEG displayed improved mechanical properties compared to pure PLA. Thermal, mechanical and morphological characterization of the blends were also conducted. © 2012 Taylor and Francis Group, LLC Daha fazlası Daha az

Acar, Merve | Çoban, Selim | Hazer, Baki

Article | 2013 | Journal of Macromolecular Science, Part A: Pure and Applied Chemistry50 ( 3 ) , pp.287 - 296

A cold water soluble, biobased polymer derived from autoxidized soya oil has been described. Oxidized soya oil polymer was obtained by exposure to air under daylight at room temperature. The thickness of the soya oil at the beginning of the reaction and the oxidation time adversely influenced the molecular weight of the soya oil polymer obtained. The oxidized soya oil polymer obtained was then reacted with diethanol amine to obtain a hydroxylated soya oil polymer. The cold water soluble hydroxylated soya oil polymer was characterized by viscosity measurements, elemental analysis, FT-IR, 1H-NMR, 13C-NMR and cosy-NMR. © 2013 Copyright . . . Taylor and Francis Group, LLC Daha fazlası Daha az

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

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

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

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