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

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

Hazer, Baki | Lenz, W. Lenz | Çakmaklı, Birten | Borcaklı, Mehlika | Koçer, Halil

Article | 1999 | Macromolecular Chemistry and Physics200 ( 8 ) , pp.1903 - 1907

Poly(3-hydroxyalkanoate)-g-poly(ethylene glycol) crosslinked graft copolymers are described. Poly(3-hydroxyalkanoate)s containing double bonds in the side chain (PHA-DB) were obtained by co-feeding Pseudomonas oleovorans with a mixture of nonanoic acid and anchovy (hamci) oily acid (in weight ratios of 50/50 and 70/30). PHA-DB was thermally grafted with a polyazoester synthesized by the reaction of poly(ethylene glycol) with MW of 400 (PEG-400) and 4,4'-azobis(4-cyanopentanoyl chloride). Sol-gel analysis and spectrometric and thermal characterization of the networks are reported. © Wiley-VCH Verlag GmbH, 1999.

Koçer, Halil | Borcaklı, Mehlika | Demirel, Songün | Hazer, Baki

Article | 2003 | Turkish Journal of Chemistry27 ( 3 ) , pp.365 - 373

Poly(3-hydroxy alkanoate)s (PHA)s are bacterial polyesters that have, due to their biodegradability and biocompatibility, attracted considerable industrial interest. All the substrates used in feeding Alcaligenes eutrophus and Pseudomonas oleovorans have been reviewed as far as we know, and some more new substrates or mixtures have been used in PHA production by microorganisms. Alcaligenes eutrophus was fed with 4-pentenoic acid, 2-hydroxy ethyl methacrylate (HEMA), corn oil acids, linseed oil acids and limonene as well as mixtures of acetic acid and glucose or lactose. Either HEMA as a sole carbon source or the mixture of glucose d . . .id not produce polyester; limonene as a sole carbon source gave few dry cells and very few mgl-1 Poly (3-hydroxy butyrate-co-3-hydroxy valerate)(PHBV) containing 5 mol-% of hydroxy valerate (HV) units. Poly(3-hydroxy butyrate), (PHB), was obtained from corn oil acids and the mixture of glucose (15 gl-1) and acetic acid (2.5 gl-1); Poly (3-hydroxy butyrate-co-3-hydroxy valerate) (PHBV) was obtained in moderate yield from 4-pentenoic acid as a sole carbon source and the rest of the substrates above. Pseudomonas oleovorans was fed with linoleic acid, laurel seed oil acids, corn oil acids, laurel leaf oil, rose oil and limonene. Medium chain length polyesters were obtained from linoleic acid, corn oil acids and laurel seed oil acids, but the others did not give any detectable polyester. The polymers obtained were characterized by size exclusion chromatography, 1H and 13C NMR, FT-IR, thermal analysis and fast atom bombardment-mass spectrometer techniques Daha fazlası Daha az

Hazer, Baki | Torul, Oktay | Borcaklı, Mehlika | Lenz, Robert W. | Fuller, R. Clinton | Goodwin, Steven D.

Article | 1998 | Journal of Environmental Polymer Degradation6 ( 2 ) , pp.109 - 113

The carboxylic acids derived from olive oil, hazelnut oil, sesame oil and hamci(anchovy) oil were evaluated as substrates for cell growth and the production of reserve polyesters by Pseudomonas oleovorans. Poly-3-hydroxyalkanoates containing both saturated (mainly 3-hydroxy-octanoate and 3-hydroxy-decanoate) and unsaturated repeating units with 8 to 20 carbon atoms, or more, were produced in 26 to 61% yields based on cell dry weights. The number average molecular weights of these polymers varied from 45,000 to 68,000 Daltons.The carboxylic acids derived from olive oil, hazelnut oil, sesame oil and hamci(anchovy) oil were evaluated a . . .s substrates for cell growth and the production of reserve polyesters by Pseudomonas oleovorans. Poly-3-hydroxy alkanoates containing both saturated (mainly 3-hydroxy-octanoate and 3-hydroxy-decanoate) and unsaturated repeating units with 8 to 20 carbon atoms, or more, were produced in 26 to 61% yields based on cell dry weights. The number average molecular weights of these polymers varied from 45,000 to 68,000 Daltons 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

Arkın, Ali Hakan | Hazer, Baki | Borcaklı, Mehlika

Article | 2000 | Macromolecules33 ( 9 ) , pp.3219 - 3223

Unsaturated biopolyesters, (PHA-DB), obtained from pure anchovy (hamci), hazelnut, soybean oily acids and the mixtures of octanoic acid (in weight ratios of 50/50 and 70/30) were chlorinated up to 54 wt % Cl content. The molecular weights (MW) of the chlorinated biopolyesters were between 1.3×104 and 3.0×104 and decreased with the increase in chlorine content in PHA-DB. Melting transitions of the chlorinated biopolyesters were between 62 and 125 °C depending on the chlorine content when compared with those of the original PHAs, 44-55 °C.