Kılıçay, Ebru | Hazer, Baki | Çoban, Burak | Scholz, Carmen

Article | 2010 | Hacettepe Journal of Biology and Chemistry38 ( 1 ) , pp.9 - 17

Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly(3- hydroxy alkanoates) (PHA)s; poly(3-hydroxy-10-undecenoate) (PHU) and poly(3-hydroxyoctanoate- co-3-hydroxy-10-undecenoate) (PHOU), respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol (PEG) in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by $^ 1H$ NMR and FT . . .IR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly(3- hydroxy alkanoates) (PHA)s; poly(3-hydroxy-10-undecenoate) (PHU) and poly(3-hydroxyoctanoate- co-3-hydroxy-10-undecenoate) (PHOU), respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol (PEG) in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by $^ 1H$ NMR and FTIR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) Daha fazlası Daha az

Yanpar, Tuğba | Hazer, Baki | Arslan, Ali

Article | 2006 | İnönü Üniversitesi Eğitim Fakültesi Dergisi7 ( 11 ) , pp.113 - 122

Bu çalışmanın amacı, oluşturmacı yaklaşıma dayalı grup aktivitelerinin etkilerini göstermektir. Bu araştırma 2001- 2002 öğretim yılı, güz döneminde Kdz. Ereğli Anadolu Lisesinde okuyan 58 öğrenci üzerinde yapılan deneysel çalışmadır. Deney grubunda oluşturmacılık temelli grup aktiviteleri, kontrol grubunda geleneksel yöntem kullanılmıştır. Veri toplama aracı olarak, bilişsel becerilerini ölçebilmek için ön ve son testler, duyuşsal algılamalarını belirlemek için açık uçlu sorular sorulmuştur. Bu çalışma grup çalışmalarının kullanıldığı sınıftaki öğrenci başarısının, geleneksel öğretim yönteminin kullanıldığı gruptaki öğrenci başarısı . . .ndan daha yüksek olduğunu göstermiştir. Ayrıca öğrencilerin oluşturmacılık temelli grup aktivitelerini algılamalarının olumlu olduğu sonucuna ulaşılmıştır. The purpose of this research was to demonstrate the effectiveness of group activities based on constructivism in chemistry course for High School. The study was carried on with 58 high school students at the beginning of the spring semester of 2001-2002. Group activities based on constructivism were performed with the experimental group while the traditional teaching style (teacher active) was performed with the control group. An achievement test and an open-ended questionnaire were used to gather the data. This study indicated that the success of the students in the experimental group in which constructivist learning approach was employed was higher than those in the control group. Therefore, it was found that the students in the experimental group perceived the group activities, based on constructivism, positively Daha fazlası Daha az

Allı, Abdulkadir | Hazer, Baki

Article | 2009 | Hacettepe Journal of Biology and Chemistry37 ( 1 ) , pp.23 - 31

A new macromonomer initiator for atom transfer radical polymerization (ATRP-MIM) based on polyethylene glycol (Mn= 660 Da) (PEG) was synthesized by the reaction of hydroxyl end of the mono-methacryloyl polyethylene glycol with 2-bromopropanoyl chloride leading to methacryloyl polyethylene glycol 2-bromopropanoyl ester (v-PEG-Br). Poly(ethylene glycol) functionalized with methacrylate at one end was reacted with 2-bromopropionyl chloride to form a macromonomeric initiator for ATRP. Self condensing ATRP-MIM polymerization yielded branched PEG with low cross-linked fraction (3-29 wt%). In the same polymerization condition, self condens . . .ing ATRP-MIM polymerization was found faster than that of conventional free radical macromonomer initiators which behave as macro crosslinker, macro initiator and macromonomer. Besides the PEG obtained has still unreacted double bonds and halides leading to the further branching. In the second step, ATRP of methyl methacrylate was initiated by the MIM-ATRP using the copper coordination complex CuBr / N,N,N’,N’,N’’-pentamethyl diethylenetriamine (PMDETA). The ATRP-MIM and the chloroform soluble branched polymers obtained were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). Variation of gel polymer content, molecular weight of the soluble parts and conversion of the monomers with the changing polymerization conditions were also discussed. A new macromonomer initiator for atom transfer radical polymerization (ATRP-MIM) based on polyethylene glycol (Mn= 660 Da) (PEG) was synthesized by the reaction of hydroxyl end of the mono-methacryloyl polyethylene glycol with 2-bromopropanoyl chloride leading to methacryloyl polyethylene glycol 2-bromopropanoyl ester (v-PEG-Br). Poly(ethylene glycol) functionalized with methacrylate at one end was reacted with 2-bromopropionyl chloride to form a macromonomeric initiator for ATRP. Self condensing ATRP-MIM polymerization yielded branched PEG with low cross-linked fraction (3-29 wt%). In the same polymerization condition, self condensing ATRP-MIM polymerization was found faster than that of conventional free radical macromonomer initiators which behave as macro crosslinker, macro initiator and macromonomer. Besides the PEG obtained has still unreacted double bonds and halides leading to the further branching. In the second step, ATRP of methyl methacrylate was initiated by the MIM-ATRP using the copper coordination complex CuBr / N,N,N’,N’,N’’-pentamethyl diethylenetriamine (PMDETA). The ATRP-MIM and the chloroform soluble branched polymers obtained were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). Variation of gel polymer content, molecular weight of the soluble parts and conversion of the monomers with the changing polymerization conditions were also discussed Daha fazlası Daha az

Allı, Abdulkadir | Şanal, Timur | Hazer, Baki

Article | 2015 | Turkish Journal of Chemistry39 ( 2 ) , pp.382 - 394

Abstract: Water soluble hydroxylated soya oil polymer was used in the redox polymerization of N-isopropylacrylamide (NIPAM) in order to obtain water-based hydroxylated-soya oil polymer-g-PNIPAM graft copolymer. For this purpose, soya oil was exposed to air under sunlight to obtain autoxidized soya oil polymer (PSy-ox). PSy-ox was allowed to react with diethanol amine to obtain hydroxylated soya oil polymer (hydroxylated-PSy). An ammonium persulfate with hydroxylated-PSy redox initiating system was used in the polymerization of NIPAM in order to obtain thermo-responsive hydroxylated-PSy-g-PNIPAM water-based graft copolymers. The graf . . .t copolymers were characterized using proton nuclear magnetic resonance, Fourier transform infrared~spectroscopy, gel permeation chromatography, thermal gravimetric analysis, and differential scanning calorimetry techniques. The effects of hydroxylated-PSy on the thermal response rate of PNIPAM and the percentage of transmittance in the water of graft copolymers were studied by means of observing UV transmittance behaviors in response to changing temperature. This showed the temperature-responsive property, and exhibited a volume phase transition from 22 °C to 29 °C, while that of PNIPAM was 32 °C. Abstract: Water soluble hydroxylated soya oil polymer was used in the redox polymerization of N-isopropylacrylamide (NIPAM) in order to obtain water-based hydroxylated-soya oil polymer-g-PNIPAM graft copolymer. For this purpose, soya oil was exposed to air under sunlight to obtain autoxidized soya oil polymer (PSy-ox). PSy-ox was allowed to react with diethanol amine to obtain hydroxylated soya oil polymer (hydroxylated-PSy). An ammonium persulfate with hydroxylated-PSy redox initiating system was used in the polymerization of NIPAM in order to obtain thermo-responsive hydroxylated-PSy-g-PNIPAM water-based graft copolymers. The graft copolymers were characterized using proton nuclear magnetic resonance, Fourier transform infrared~spectroscopy, gel permeation chromatography, thermal gravimetric analysis, and differential scanning calorimetry techniques. The effects of hydroxylated-PSy on the thermal response rate of PNIPAM and the percentage of transmittance in the water of graft copolymers were studied by means of observing UV transmittance behaviors in response to changing temperature. This showed the temperature-responsive property, and exhibited a volume phase transition from 22 °C to 29 °C, while that of PNIPAM was 32 °C Daha fazlası Daha az

Yapar, Tuğba | Hazer, Baki

Article | 2003 | Süleyman Demirel Üniversitesi Burdur Eğitim Fakültesi Dergisi4 ( 6 ) , pp.85 - 98

Bu çalışmada kimyasal maddeler konusunda tümevarım ve tümdengelim içerik yaklaşımları karşılaştırılmıştır. Tümevarım içerik sırasında atomun yapısı ve priyodik tablo, kimyasal bağlar, moleküller arası çekim kuvvetleri, sıvı, katı ve gazların özellikleri ve kimyasal maddeler üniteleri sırasıyla işlenirken, tümdengelimde tam tersi bir sırayla üniteler işlenmiştir. Bu araştırma 1999-2000 güz döneminde 74 öğrenci ile yapılmıştır. Bilişsel işlem beceri testi, çoktan seçmeli test ve yazılı sınav kullanılmıştır. Gözlem ve görüşmede yapılmıştır. Veriler MANOVA istatistiği ile analiz edilmiştir. Yazılı sınava göre gruplar arasında anlamlı fa . . .rklar bulunmuştur. Gözlem ve görüşme sonuçları tümevarım içerik sırasının tümdengelime gore öğrenciler üzerinde daha pozitif etkisi olduğunu göstermektedir The comparison of inductive and deductive content sequence of the concept of chemical substances has been studied. Inductive content sequence was ordered in the structure of atom and periodic table, chemical bonding, intermolecular forces and properties of liquids and solids and chemical substances, while deductive content sequence was reverse. This research was applied on 74 freshman students in 1999-2000 spring terms. The students were equally divided in to two groups which one of the group took chemistry course in deductive content sequence and the other group took inductive content sequence. Science process skill test, multiple choice test and essay type test were applied on these students. Observations and interviews with some students were also made during the course. The data obtained from the tests were analyzed with Multivariate analysis of Variance (MANOVA). After the completion of the content sequence, the students who took the course in inductive content sequence, achieved better than students who took the course in deductive content sequence on essay type test results. Additionally gender resulted not significant on dependent variables. Observations and interviews results indicated that inductive content sequence had positive effect on the students Daha fazlası Daha az