Arkin, Ali Hakan | Hazer, Baki | Adamus, Grazyna | Kowalczuk, Marek | Jedlinski, Zbigniew | Lenz, Robert W.

Editorial | 2001 | BIOMACROMOLECULES2 ( 3 ) , pp.623 - 627

Synthesis of an a,beta-alkyl branched polyester, i.e., poly(2-methyl-3-hydroxyoctanoate), has been accomplished via anionic polymerization of alpha-methyl-beta-pentyl-beta-propiolactone mediated by supramolecular complexes of potassium methoxide or potassium hydroxide, respectively. The structure of resulting polymers has been established by electrospray ionization multistage mass spectrometry (ESI-MSn), FT-IR, NMR, and GPC analyses. Previously proposed addition-elimination mechanism of the polymerization of beta-lactones containing alpha-hydrogen by alkoxide anion has been confirmed to operate also in the case of beta-lactone havin . . .g alkyl substituents in both alpha and beta positions Daha fazlası Daha az

Arslan, Hülya | Eroğlu, Mehmet S. | Hazer, Baki

Article | 2001 | European Polymer Journal37 ( 3 ) , pp.581 - 585

Polymerization of methyl methacrylate initiated by ceric ammonium nitrate in combination with poly(glycidyl azide)-diol was investigated in aqueous nitric acid. Poly(methyl methacrylate)-b-poly(glycidyl azide) copolymer was obtained. Block copolymer yield was increased using tetrabutyl ammonium hydrogen sulphate as a surfactant. The effect of nitric acid, ceric ions and diol concentration on the block copolymer yield was investigated. Block copolymers were characterized using GPC, 1H-NMR, FTIR, DSC, TGA and fractional precipitation methods.

Çakmaklı, Birten | Hazer, Baki | Borcaklı, Mehlika

Article | 2001 | Macromolecular Chemistry and Physics202 ( 16 ) , pp.348 - 354

A new soluble terephthaloyl oligoperoxide (OTP) was synthesized by the reaction of terephthaloyl. peroxide and 2,5-dimethyl 2,5-dihydroperoxy hexane. Thermal polymerization of vinyl monomers (styrene, methyl methacrylate) with OTP yielded poly(styrene peroxide) (PS-P) and poly(methyl methacrylate peroxide) (PMMA-P) which are used in the grafting reactions onto medium chain length unsaturated bacterial polyester obtained from soybean oily acids with Pseudomonas oleovorans poly(3-hydroxy alkanoate), (PHA). PS-g-PHA and PMMA-g-PHA graft copolymers isolated from related homopolymers were characterizated by 1H NMR spectrometry, FT-IR spe . . .ctroscopy, thermal analysis and gel permeation chromatographic (GPC) techiques. Swelling measurement of the crosslinked graft copolymers were also measured to calculate qv values Daha fazlası Daha az

İlter, Songun | Hazer, Baki | Borcaklı, Mehlika | Atıcı, Oya

Article | 2001 | Macromolecular Chemistry and Physics202 ( 11 ) , pp.2281 - 2286

Poly(3-hydroxy alkanoate) containing unsaturated side chains was produced by feeding Pseudomonas oleovorans with soybean-oil acid (PHA-soybean). The composition of PHA-soybean were found to be 10 mol-% of unsaturated side chains with the saturated hexanoate, octanoate and decanoate units. Methyl methacrylate (MMA) was thermally grafted on PHA-soybean in the presence of benzoyl peroxide. Fractional precipitation was used to isolate the graft copolymer from related homopolymers. PHA content in copolymer samples was between 15 to 30 mol-%. Graft copolymer samples were kept in hydroquinone to prevent post polymerization leading to cross . . .linking in a day under laboratory atmospheric conditions. Copolymer characterization was performed using GPC and NMR techniques. Thermal analysis of the graft copolymer indicated the decomposition and glass transition temperatures of the PHA and PMMA segments of the graft copolymers. They also showed elongation at break in the range 10 to 21 related to the plasticizer effect of the biopolyester segments Daha fazlası Daha az

Hazer, Baki | Demirel, Songun I. | Borcaklı, Mehlika | Eroğlu, Mehmet S. | Çakmak, Miko | Erman, burak

Article | 2001 | Polymer Bulletin46 ( 5 ) , pp.389 - 394

Poly(-3-hydroxy alkanoate) containing unsaturated side chains, PHA-soybean, were produced by feeding Pseudomonas oleovorans with soybean oily acids obtained from soybean oil. Unsaturation of PHA-soybean were found to be 10 mol-% of unsaturated side chains. Main saturated part of the biopolymer was Poly(3-hydroxy octanoate) with minor hexanoate and decanoate units. PHA films were crosslinked via free radical mechanism by means of thermally or under UV irradiation in the presence of benzoyl peroxide, benzophenon, and/or ethylene glycol dimethacrylate (EGDM). Crosslinking yield of the PHA films were found to be from 81 to 93 wt.-% from . . . the sol-gel analysis. Swelling properties of the crosslinked PHA films in chloroform and toluene were also studied. Mc values of crosslinked PHAs were also calculated using Flory-Rehner equation. The crosslinked biopolyester obtained by thermally at 60 °C with benzoyl peroxide indicated the highest crosslinking density. Glass transition temperatures (Tg) of crosslinked biopolyester samples were changed from -33 to -45 °C while that of PHA-soybean was -60 °C Daha fazlası Daha az