Hazer, Baki | Akyol, Elvan | Şanal, Timur | Guillaume, Sophie | Çakmaklı, Birten | Steinbuchel, Alexander

Article | 2019 | Polymer Bulletin76 ( 2 ) , pp.919 - 932

Poly(3-hydroxyalkanoate)s (PHAs) are a class of polymers receiving attention because of their potential as renewable, biodegradable and high-technology properties. Unlike most short chain length (scl) PHAs such as poly(3-hydroxybutyrate) (PHB), medium chain length (mcl) PHAs such as poly(3-hydroxyoctanoate) (PHO) exhibit low crystallinity and are elastomeric in character. PHB-b–PEG-b–PHO block copolymers can combine both properties in block copolymer matrix. In this study, we report the synthesis of the block copolymers combining the PHB and PHO blocks. Transamidation reactions of PHB with polyethylene glycol with primary amine yiel . . .d equimolar amounts and PHB with amine ends. PHO reacts with the modified PHB containing the amine end to give PHB-b–PEG-b–PHO block copolymers. Structural analysis of the products was performed by using 1H–, 13C, heteronuclear single quantum coherence NMR techniques. Thermal and mechanical properties of the block polymers were also evaluated. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature Daha fazlası Daha az

İnce, Özge | Akyol, Elvan | Sulu, Elvan | Şanal, Timur | Hazer, Baki

Article | 2016 | Journal of Polymer Research23 ( 1 ) , pp.1 - 10

Synthesis of novel poly (styrene)-g-poly(linoleic acid)-g-poly(ethylene glycol) amphiphilic rod-coil tadpole and poly (styrene)-g-poly(linoleic acid)-g-poly (dimethyl siloxane) double hydrophobic rod-coil tadpole graft copolymers have been reported. In the first step, poly(linoleic acid) peroxide macro initiator (PLina) was prepared by exposing linoleic acid to air at room temperature for three weeks, in view of the autoxidation process. In the second step, poly styrene-g-poly linoleic acid graft copolymer (PLinaS) was prepared by the polymerization of styrene initiated by PLina. In the third step, PS-g-PLina-g-PEG rod-coil tadpole . . .amphiphilic graft copolymer and PS-g-PLina-g-PolyPDMS rod-coil tadpole double hydrophobic graft copolymers were obtained by the reaction of carboxylic ends of PLinaS with polyethylene glycol (PEG) with primary amine terminal and poly (dimethyl siloxane) (PDMS) with primary amine terminals. The target copolymers and all intermediates were well characterized by GPC, FTIR, 1H NMR, DSC, and TGA in detail. © 2015, Springer Science+Business Media Dordrecht Daha fazlası Daha az

Hazer, Baki | Akyol, Elvan

Article | 2016 | JAOCS, Journal of the American Oil Chemists' Society93 ( 2 ) , pp.201 - 213

Polyunsaturated plant oils have gained great interest as monomers to produce biodegradable polymers obtained from renewable resources due to the limited existing sources of petroleum oil and environmental issues. Soybean oil was autoxidized by exposure to atomospheric oxygen at room temperature with or without the presence of gold nanoparticles (Au NPs) 5-41 days. When the autoxidation process was catalyzed with Au NPs, the molecular weight of the oxidized oil was increased in 5 days. In contrast to this, without Au NPs, the oxidized oil was still a fluidized liquid. Autoxidized soybean oil polymer in toluene solution with gold NP s . . .howed a surface plasmon resonance at ?max = 540 nm in a UV-VIS spectrometer and a fluorescence emission spectrum at ?max = 450 nm, when it was irradiated at ?max = 390 nm. The higher molecular weight of the polymeric oils was successively fractionated by the extraction from the solvent-non-solvent mixture CHCl3/petroleum ether with the volume ratio of 5:15. Three polymeric oils fractions with different molecular weight (ca 1000, 4000, and 40,000 g/mol) were obtained. GC-MS analysis, 1H-NMR and GPC techniques were used in the structural analysis of the fractionated polymeric oils. © 2015 AOCS Daha fazlası Daha az

Aydın, R. Seda Tığlı | Akyol, Elvan | Hazer, Baki

Article | 2017 | JAOCS, Journal of the American Oil Chemists' Society94 ( 3 ) , pp.413 - 424

Due to the great interest in oil-based polymers, which are prepared from renewable resources, different forms and amounts of soybean oil-based PLA films were prepared and evaluated for their potential usage as a medical biomaterial. Soybean oil, epoxidized soybean oil and auto-oxidized soybean oil were blended with PLA and PLA/oil films with appropriate oil amounts [2, 7, 14 and 20% (w/w)] were obtained by solvent casting. Thermal stability and plasticization effect were determined by adjusting oil amounts and type. Epoxidized soybean oil blended films showed the smallest increase in elongation breaks (13–20%) and the highest decrea . . .se in thermal decomposition temperatures (364–327 °C) compared to other oil blended films. In vitro quantitative and qualitative cytotoxicity results showed no reactivity (grade 0) for the L929 cells treated with 14% (w/w) oil blended PLA films. In vivo irritation and implantation tests concluded that 14% (w/w) oil blended PLA films were non-irritant. No erythema, no oedema reactions, no traumatic necrosis and foreign debris were observed. Thus, along with superior biocompatibility, PLA/oil films can replace petroleum-based products for several biomedical uses. © 2017, AOCS Daha fazlası Daha az

Aydın Tığlı, R. Seda | Akyol, Elvan | Hazer, Baki

Article | 2018 | Journal of Polymers and the Environment26 ( 3 ) , pp.1262 - 1271

Controlling the degradation parameters is one of the main challenges of preparing appropriate biomaterials for biomedical applications. In this study, the effect of soybean oil inclusion on hydrolytic degradation of polylactic acid (PLA) was investigated both in vitro and in vivo. PLA/oil membranes were prepared by using polymeric soybean oil (PSO), epoxidized soybean oil and soybean oil (SOYA) with their varied concentrations. Degradation of membranes was performed in vitro for 8 weeks period and in vivo for 4 weeks period. Weight loss, changes in molecular weight, thermal properties and morphological changes were studied during de . . .gradation. SOYA blended PLA membranes show the lowest degradation rates by bulk degradation after 4 weeks in vitro, followed by surface erosion for the first week. Approximately twofold high percentage weight losses of all membranes were obtained after 4 weeks of degradation in vivo in comparison with in vitro data. The significant weight loss, molecular weight loss and thermal property change for PSO blended membranes were determined during in vivo degradation which highlights the increase of degradation rate by bulk degradation. Drastic morphological changes were observed on surface of degraded membranes in vivo with large pores, cracks, fissures and large cavities. © 2017, Springer Science+Business Media New York Daha fazlası Daha az