Bulunan: 8 Adet 0.001 sn
Koleksiyon [8]
Tam Metin [2]
Yayın Türü [3]
Yazar [20]
Konu Başlıkları [20]
Yayıncı [1]
Yayın Dili [1]
Dergi Adı [7]

Arslan, Hülya | Yeşilyurt, Nazlı | Hazer, Baki

Proceedings | 2008 | MACROMOLECULAR SYMPOSIA269 , pp.23 - 33

4th European Symposium on Biopolymers -- OCT 02-04, 2007 -- Kusadasi, TURKEY WOS: 000258909100006

Post polymerization of saturated and unsaturated poly(3-hydroxy alkanoate)s

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

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

Poly(N-isopropylacrylamide) thermoresponsive cross-linked conjugates containing polymeric soybean oil and/or polypropylene glycol

Allı, Abdulkadir | Hazer, Baki

Article | 2008 | European Polymer Journal44 ( 6 ) , pp.1701 - 1713

Synthesis, characterization and solution properties of a new series of the PNIPAM-soybean oil and/or polypropylene glycol, PPG, conjugates (conjugates also referred to as co-networks) have been described. For this purpose free radical polymerization of NIPAM monomer was initiated by macroinitiators based on PSB and/or PPG in order to obtain PSB-g-PNIPAM, PPG-g-PNIPAM and PSB-g-PPG-g-PNIPAM cross-linked graft copolymers. The autooxidation of soybean oil under air at room temperature rendered waxy soluble polymeric soybean oil peroxide associated with cross-linked parts. The soluble polymeric oil macro-peroxide isolated from the cross . . .-linked part was used to initiate the free radical polymerization of NIPAM to give PSB-g-PNIPAM cross-linked copolymer. To obtain PPG-macromonomeric initiator, PPG-MIM, PPG-bis amino propyl ether with Mn 400 (or 2000) Dalton was reacted with 4,4'-azo bis cyanopentanoyl chloride and methacryloyl chloride, respectively. PPG-MIM also initiated the free radical polymerization of NIPAM at 80 °C to yield PPG-g-PNIPAM cross-linked thermoresponsive product. In order to obtain PSB-g-PPG-g-PNIPAM cross-linked triblock copolymer, NIPAM was polymerized by using the mixture of two macroinitiators, PSB and PPG-MIM. PSB contents in the graft copolymers were calculated via elemental analysis of nitrogen in graft copolymers. Thermal analysis, SEM, FTIR and 1H NMR techniques were used in the characterization of the products. The effect of polymeric soybean oil, PSB, and/or PPG on the thermal response rate of poly(N-isopropylacrylamide, PNIPAM, cross-linked-graft copolymers swollen in water has been investigated by means of swelling-deswelling and drug release behaviors against to temperature change. Lower critical solution temperatures (LCST) of the cross-linked PNIPAM conjugates (conjugates also referred to as co-networks) were determined from the curves of swelling degrees versus solution temperatures. The response temperature of the hydrophobically modified PNIPAM conjugates was reduced to 27 °C, 23 °C and 27 °C for PSB-g-PNIPAM, PPG-g-PNIPAM and PSB-g-PPG-g-PNIPAM, respectively. We have found that the graft copolymers were not pH-responsive. In addition, higher pH ranges cause the hydrolysis of the PSB ester linkages, quickly and makes the cross-linked graft copolymers soluble. The fastest shrinking of the gels was observed by loosing water between 65% and 98% at 50 °C. Methyl orange (MO), was used as a model drug, loaded into cross-linked graft copolymers to examine and compare the effects of controlled release at lower and higher temperatures of lower critical solution temperature (LCST). © 2008 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Preparation and characterization of triamcinolone acetonide-loaded poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) microspheres

Bayram, Cem | Denkbaş, Emir Baki | Kılıçay, Ebru | Hazer, Baki | Çakmak, Hasan Basri | Noda, Isao

Article | 2008 | Journal of Bioactive and Compatible Polymers23 ( 4 ) , pp.334 - 347

Triamcinolone acetonide loaded in poly(3-hydroxybutyrate-co-3 hydroxyhexanoate) (PHBHx) microspheres were prepared to treat cystoid macular oedema (CMO) and acute posterior segment inflammation associated with uveitis. The PHBHx microspheres were prepared by solvent evaporation technique using methylene chloride as the solvent and aqueous poly(vinyl alcohol) emulsifier as the dispersion medium. The PHBHx microspheres obtained were well formed with narrow size distribution; the average size prepared ranged from 40-200 µm depending on the formulation used. The stirring rate of the dispersion medium, emulsifier concentration, and polym . . .er/solvent ratio parameters were varied to determine their effect on the size and size distribution of the PHBHx microspheres. Increasing the stirring rate and emulsifier concentration decreased the size and the size distribution of the microspheres, while increasing the polymer/solvent ratio caused the opposite effect. The polymer/drug ratio was the most effective parameter for controlling drug loading and release properties. More than 90% of the loaded drug was released within the first 24 h; after that, the release rate was slower for all formulations. © SAGE Publications 2008 Daha fazlası Daha az

Autooxidized polyunsaturated oils/oily acids: Post-it applications and reactions with Fe(III) and adhesion properties

Keleş, Elif | Hazer, Baki

Proceedings | 2008 | Macromolecular Symposia269 ( 1 ) , pp.154 - 160

Soybean oil, sesame oil, linoleic acid and linolenic acid were epoxidized, peroxidized and hydroperoxidized via autooxidation under air oxygen and sunlight at room temperature to obtain novel post-it materials. Polymeric soybean oil peroxide and sesame oil peroxide were containing soluble part of 60%(w/w) together with crosslinked part of 40%(w/w) while polymeric linoleic and polymeric linolenic acids were completely soluble. The autooxidized soluble products with Mn varying between 800 and 3100 Daltons were used as post-it adhesive. The highest adhesion was observed in the case of polymeric soybean oil (3.0 Newton), while adhesion . . .of commercial epoxidized soybean oil, polymeric linoleic and polymeric linolenic acid were 0.8, 0.5 and 0.5 Newton, respectively. Reactions of the autooxidized soluble products with Fe(NO 3)3. 4H2O in the presence of ethanol, glycerol and diethyleneglycol gave the hydroxy functionalized products with the same Mn values and indicating no adhesive properties. When the commercial epoxidized soybean oil was reacted with Fe(NO3)3. 4H 2O in the presence of the alcohols, Mn of the hydroxy functionalized polymeric oil was found to be unchanged. 1H NMR, FT-IR, SEM and GPC techniques were used in the characterization of the products obtained. Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA Daha fazlası Daha az

Effect of thermal treatments and palladium loading on hydrogen sorption characteristics of single-walled carbon nanotubes

Kocabaş, Sefa | Kopaç, Türkan | Doğu, Gülsen | Doğu, Timur

Article | 2008 | International Journal of Hydrogen Energy33 ( 6 ) , pp.1693 - 1699

The effects of thermal treatments and palladium loading on sorption characteristics of single-walled carbon nanotube (SWCNT) samples were investigated. The thermal treatment experiments were carried out in a temperature range of 300-800 °C. The sorption characteristics of nitrogen and hydrogen on the original, heat treated and the palladium loaded samples were investigated. Analyzing the nitrogen adsorption isotherms on these samples at 77.4 K, the highest specific surface area of 2230 m2 / g was obtained at 575 °C, while the original samples had a specific surface area of 230 m2 / g. The highest surface area samples obtained at 575 . . . °C were loaded by 3.3, 6.3 and 10.1 wt% palladium and hydrogen adsorption isotherms on these samples were obtained at 77.4 K. The hydrogen sorption capacities of the original and the 10.1 wt% palladium loaded samples were found to be 0.76 and 1.66 wt%, respectively. It was shown that by controlling the temperature of heat treatment, the specific surface area of the samples could be increased and the spillover effect of palladium could enhance the hydrogen sorption. © 2008 International Association for Hydrogen Energy Daha fazlası Daha az

{N,N'-Bis[1-(2-pyrid-yl)ethyl-idene]ethane-1,2-diamine-4 N,N',N'',N'''}bis-(trifluoro-methane- sulfanato-?O)copper(II)

Coles, Simon J. | Şengül, Abdurrahman | Kurt, Özgür | Altın, Safinaz

Article | 2008 | Acta Crystallographica Section E: Structure Reports Online64 ( 11 ) , pp.1693 - 1699

A discrete neutral CuII complex, [Cu(CF3SO3)2(C16H18N4)], has been derived from the symmetrical tetra-dentate Schiff base, N,N'-bis-[1-(pyridin-2-yl)ethyl-idene]ethane-1,2-diamine. The copper centre assumes a tetra-gonally distorted pseudo-octa-hedral geometry with the O atoms of two trifluoro-methane-sulfonate anions coordinated weakly in the axial positions. The Cu - N distances lie in the range 1.941 (3)-2.011 (3) Å and the Cu - O distances are 2.474 (3) and 2.564 (3) Å.

6698 sayılı Kişisel Verilerin Korunması Kanunu kapsamında yükümlülüklerimiz ve çerez politikamız hakkında bilgi sahibi olmak için alttaki bağlantıyı kullanabilirsiniz.

Bu site altında yer alan tüm kaynaklar Creative Commons Alıntı-GayriTicari-Türetilemez 4.0 Uluslararası Lisansı ile lisanslanmıştır.