Erduranlı, Haydar | Hazer, Baki | Borcaklı, Mehlika

Conference Object | 2008 | Macromolecular Symposia269 ( 1 ) , pp.161 - 169

Chemical modification is useful to diversify poly(3-hydroxyalkanoate)s, for medical and industrial applications. In this manner, transesterification reactions of poly(3-hydroxy butyrate) were carried out under reflux condition of 1,2-dichlorobenzene in the presence of 1,4-butane diol, poly(ethyleneglycol) bis(2-aminopropyl ether) with molecular weights of 1000 and 2000, poly(ethylene glycol)methacrylate or glycerol at 180°C. Addition reactions of bromine and -SH groups of 3-mercaptopropionic acid to the double bond of poly(3-hydroxy-io-undecenoate) were also carried out. Functionalized poly(3-hydroxyalkanoate)s were characterized us . . .ing 1H NMR, FTIR, GPC and thermal analysis techniques. Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA Daha fazlası Daha az

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

Arslan, Hülya | Menteş, Ayfer | Hazer, Baki

Article | 2004 | Journal of Applied Polymer Science94 ( 4 ) , pp.1789 - 1796

A poly[(R,S)-3-hydroxybutyrate] macroinitiator (PHB-MI) was obtained through the condensation reaction of poly[(R,S)-3-hydroxybutyrate] (PHB) oligomers containing dihydroxyl end functionalities with 4,4'-azobis(4-cyanopentanoyl chloride). The PHB-MI obtained in this way had hydroxyl groups at two end of the polymer chain and an internal azo group. The synthesis of ABA-type PHB-b-PMMA block copolymers [where A is poly(methyl methacrylate) (PMMA) and B is PHB] via PHB-MI was accomplished in two steps. First, multiblock active copolymers with azo groups (PMMA-PHB-MI) were prepared through the redox free-radical polymerization of methyl . . . methacrylate (MMA) with a PHB-MI/Ce(IV) redox system in aqueous nitric acid at 40°C. Second, PMMA-PHB-MI was used in the thermal polymerization of MMA at 60°C to obtain PHB-b-PMMA. When styrene (S) was used instead of MMA in the second step, ABCBA-type PMMA-b-PHB-b-PS multiblock copolymers [where C is polystyrene (PS)] were obtained. In addition, the direct thermal polymerization of the monomers (MMA or S) via PHB-MI provided AB-type diblocks copolymers with MMA and BCB-type triblock copolymers with S. The macroinitiators and block copolymers were characterized with ultraviolet-visible spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, cryoscopic measurements, and thermogravimetric analysis. The increases in the intrinsic viscosity and fractional precipitation confirmed that a block copolymer had been obtained. © 2004 Wiley Periodicals, Inc Daha fazlası Daha az