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Öğe Characterization of some di-block copolymers and investigation of their temperature-dependent structural behaviors(Int Union Crystallography, 2011) Orujalipoor, Ilghar; Tukel, Caner; Celik, Omer; Ide, Semra; Genli, Nasrettin; Degirmenci, Mustafa[Abstract Not Available]Öğe Facile “Green” synthesis of a novel Co–W–B catalyst from Rheum ribes shell extract and its effect on sodium borohydride hydrolysis: Kinetic mechanism(Elsevier Ltd., 2023) Ekinci, Arzu; Genli, Nasrettin; Şahin, Ömer; Baytar, OrhanThe present investigation aimed to assess the influence of the Co–W–B NPs catalyst on the process of sodium borohydride hydrolysis. The study involved the synthesis of Co–W–B NPs through the utilization of an eco-friendly green synthesis extract derived from the Rheum ribes shell in conjunction with the chemical reduction technique for catalyst production. The investigation of catalysts' structure and surface morphology was conducted through the utilization of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) techniques. The average particle size was determined to be 35 nm in TEM analysis. The presence of Co–W–B nanoparticles and their elemental composition % were determined through EDX analysis, revealing values of 63.9% (Co), 31.89% (C), 1.75% (B), and 2.46% (W) within the nanoparticle. The manufactured Co–W–B catalyst's use for hydrolysis of sodium borohydride was studied under various conditions, including different concentrations of NaOH and NaBH4, different amounts of catalyst, and different temperature parameters. The hydrogen production rate for the Co–W–B NPs catalyst in NaBH4 hydrolysis was determined to be 5367 mLg−1min−1 at 30 °C. The study involved the determination of TOF values for a catalyst composed of Co–W–B NPs, which were subjected to varying temperatures. The activation energies were determined through the utilization of the n-th order and Langmuir-Hinshelwood kinetic models and subsequently calculated using the Arrhenius equation, resulting in values of 35.36 and 31.70 kJ/mol, respectively. The values of enthalpy and entropy, ΔH and ΔS, were determined through the utilization of Eyring's equation, 18.49 kJ/mol and −80.7 J/mol.K, respectively.Öğe Green synthesis of Co-based nanoparticles from Rheum ribes shell extract and determination of the effect of their activity on sodium borohydride hydrolysis(Springer Science and Business Media Deutschland GmbH, 2024) Baytar, Orhan; Şahin, Ömer; Genli, Nasrettin; Ekinci, ArzuAbstract This study investigated the effect of Co(0) and Co-B NP catalysts synthesized by the green synthesis method using Rheum ribes shell extract on the NaBH4 hydrolysis process for the first time, and determined the role of the green synthesis method in the catalyst activity. The investigation of the structure and surface morphology of the catalysts was evaluated using XRD, SEM–EDX, TEM, FTIR, and XPS analyses. The effect of catalysts on NaBH4 was examined at different catalyst amounts, different NaBH4/NaOH concentrations, and different temperature values. The Co(0) and CoB NPs catalysts achieved the greatest HGR values at a solution temperature of 30 °C, with values of 7326 mLmin−1g−1cat and 12,524 mLmin−1g−1cat, respectively. The calculated activation energies for Co(0) and Co-B NPs catalysts are 37.68 kJmol−1 and 21.28 kJmol−1, respectively. The green synthesis method synthesized Co(0) and Co-B catalysts significantly increased hydrogen production activity compared to the cobalt-based catalysts synthesized by other methods.Öğe Preparation and characterization of activated carbon from hydrochar by hydrothermal carbonization of chickpea stem: an application in methylene blue removal by RSM optimization(Taylor & Francis, 2022) Genli, Nasrettin; Kutluay, Sinan; Baytar, Orhan; Şahin, ÖmerHerein, mesoporous activated carbon (AC) was prepared through potassium hydroxide (KOH) activation of hydrochar derived from the hydrothermal carbonization (HTC) of chickpea stem (CS), and successfully applied to remove methylene blue (MB) dye from aqueous solutions in a batch system. The HTC-CSAC was prepared depending on different impregnation ratios (hydrochar:KOH, 50-150%), impregnation times (12-48h), activation temperatures (400-600 degrees C) and activation times (30-60min). To define HTC-CSAC, various analytical techniques such as iodine adsorption number (IAN), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) were used. In the removal process of MB by the best HTC-CSAC with a high IAN of 887mg g(-1) obtained under conditions including impregnation ratio of 70%, activation time of 45min, activation temperature of 600 degrees C and impregnation time of 24h, the effects of adsorption parameters such as pH factor (2-10), adsorbent dosage (50-100mg), initial MB concentration (40-80mg/L) and contact time (90-180min) were studied. Besides, a detailed evaluation of the adsorption mechanism for the removal of MB by HTC-CSAC was performed. The Langmuir model indicated the best isotherm data correlation, with a maximum monolayer adsorption capacity (Q(max)) of 96.15mg g(-1). The adsorption isotherm findings demonstrated that the MB removal process is feasible, and that this process takes place through the physical interaction mechanism. Additionally, the HTC-CSAC adsorbent exhibited a high regeneration and reuse performance in MB removal. After five consecutive adsorption-desorption cycles, HTC-CSAC maintained the reuse efficiency of 77.86%. As a result, the prepared HTC-CSAC with a high BET surface area of 455m(2) g(-1) and an average pore diameter of 105 angstrom could be recommended as a promising and reusable adsorbent in the treatment of synthetic dyes in wastewaters.Öğe Synthesis and characterization of an A2B2-type miktoarm star copolymer based on poly(?-caprolactone) and poly(cyclohexene oxide)(Springer, 2019) Uyar, Zafer; Genli, Nasrettin; Cay, Bahri; Arslan, Ulku; Durgun, Mustafa; Degirmenci, MustafaAn A(2)B(2)-type miktoarm star copolymer with two linear poly(epsilon-caprolactone) (PCL) and two linear poly(cyclohexene oxide) (PCHO) arms was synthesized by using ring-opening polymerization (ROP), click chemistry, and photoinduced cationic polymerization, respectively. The ROP of epsilon-CL with a dihydroxy functional initiator, 3-cyclohexene-1,1-dimethanol, produced a well-defined two-arm PCL with a cyclohexene end-functional group, (PCL)(2)-CH. The subsequent bromination of (PCL)(2)-CH followed by azidation gave a diazido end-functionalized PCL, (PCL)(2)-(N-3)(2). Then, a well-defined two-arm PCL macrophotoinitiator with benzoin end-functional groups, (PCL)(2)-(PI)(2), was prepared by the azide/alkyne click reaction of this (PCL)(2)-(N-3)(2) and PI-alkyne, a separately prepared benzoin photoinitiator bearing a terminal alkyne group. Solid data obtained from the H-1 NMR, FT-IR, GPC, UV, and fluorescence spectroscopic studies proved the successful formation of the macrophotoinitiator having a core connected to two PCL chains and two benzoin photofunctional groups (PI). Finally, a novel A(2)B(2)-type miktoarm star copolymer was synthesized via photoinduced free radical-promoted cationic polymerization of cyclohexene oxide (CHO) monomer using (PCL)(2)-(PI)(2) as photoinitiator. The obtained star copolymer consists of two PCL arms as A blocks and two PCHO arms as B blocks, (PCL)(2)-(PCHO)(2), and was characterized by H-1 NMR, FT-IR, and GPC measurements. The thermal behaviors of all the intermediate and final polymers were studied by thermogravimetric and differential thermal analysis (TG/DTA).Öğe Synthesis and characterization of epoxy-chain end(s) functional macromonomer of polystyrene and its use in photoinitiated cationic polymerization(Springer, 2014) Degirmenci, Mustafa; Genli, NasrettinA novel epoxy chain-end(s) functional polystyrene macromonomer (PSt-CHO) was prepared via free radical polymerization (FRP) of styrene (St) initiated by 4,4'-azobis(3-cyclohexenylmethyl-4-cyanopentanoate) (ACCP) azo initiator and epoxidation on workup with 3-chloroperoxybenzoic acid under inert atmosphere in methylene chloride at 0 degrees C. 4,4'-Azobis(4-cyanopentanoyl chloride) (ACPC) was obtained by the reaction of 4,4'-azobis(4-cyanopentanoic acid) (ACPA) with phosphorus pentachloride in methylene chloride. The ACCP was synthesized by the condensation reaction of 3-cyclohexene-1-methanol with ACPC. The FRP of styrene with ACCP has yielded polystyrene with cyclohexene end(s) group (PSt-CH). Epoxidation of the PSt-CH was performed using 3-chloroperoxybenzoic acid to obtain epoxy chain-end(s) functional polystyrene macromonomer (PSt-CHO). This macromonomer was used as precursor in photoinitiated cationic polymerization for obtaining brush-type and graft copolymers. Photoinitiated cationic homopolymerization of the macromonomer in the presence of diphenyliodonium salt at lambda = 300 nm yielded brush-type polymers. Photoinitiated cationic copolymerization of the macromonomer with cyclohexene oxide (CHO) monomer and diphenyliodonium salt at lambda = 350 nm produced graft copolymers. The polymers synthesized were characterized by means of FTIR, (HNMR)-H-1 and gel permeation chromatography measurements. All the spectroscopic studies revealed that a macromonomer of polystyrene with cyclohexene oxide (CHO) functionality at the chain end(s) (PSt-CHO) and their brush-type and graft copolymers were obtained.Öğe Synthesis and characterization of mid-chain macrophotoinitiator of poly(?-caprolactone) by combination of ROP and click chemistry(Springer, 2014) Degirmenci, Mustafa; Sarac, Mehmet Akif; Genli, NasrettinWell-defined mid-chain functional macrophotoinitiator of poly(epsilon-caprolactone) (PCL-PI-PCL) was synthesized by combination of ring-opening polymerization (ROP) and click chemistry strategy. Dibromo functional photoinitiator (Br-PI-Br) was prepared by the condensation of 2-bromopropanoyl bromide with 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl propan-1-one (PI). Subsequently, terminal bromo groups in Br-PI-Br were converted to azido groups to form diazido functional photoinitiator (N-3-PI-N-3) using NaN3. Well-defined precursor alkyne-functionalized PCL (alkyne-PCL) was prepared by ROP of epsilon-CL in the presence of propargyl alcohol as the initiator and stannous-2-ethylhexanoate (Sn(Oct)2) as the catalyst. Finally, the alkyne-functionalized PCL was coupled with N-3-PI-N-3 with high efficiency by click chemistry. The spectroscopic studies showed that low-polydispersity PCL with desired photoinitiator functionality in the middle of the chain was obtained.Öğe Synthesis of a well-defined end-chain macrophotoinitiator of poly(? - caprolactone) by combination of ring-opening polymerization and click chemistry(Springer, 2014) Degirmenci, Mustafa; Besli, Pinar Atuk; Genli, NasrettinA novel well-defined end-chain functional macrophotoinitiator of poly(epsilon - caprolactone) (BPI-PCL) with controlled molecular weight and narrow molecular weight distribution was successfully synthesized by combination of ring opening polymerization (ROP) and click chemistry. The synthetic procedure for the preparation of a macrophotoinitiator involves three steps: (1) an azido-functionalized benzoin photoinitiator (BPI-N-3) by transformation of a bromine-end group of BPI-Br compound into an azido group using NaN3; (2) an alkyne end-functionalized PCL (alkyne-PCL) precursor by ROP of epsilon - caprolactone (epsilon - CL) using propargyl alcohol as the initiator and stannous-2-ethylhexanoate (Sn(Oct)(2)) as the catalyst; and (3) BPI-PCL through click reaction between alkyne-PCL and BPI-N-3 using Cu(I) as a catalyst. The H-1 NMR, FTIR, UV-vis, fluorescence and gel permeation chromatography techniques were used to characterize the chemical structures of the intermediates and the target macrophotoinitiator. The obtained BPI-PCL macrophotoinitiator was used as a precursor in photoinitiated free radical promotedcationic polymerization to synthesize a poly(epsilon - caprolactone)-poly(cyclohexene oxide) (PCL-PCHO) block copolymer. The thermal behavior of the polymers was studied by differential thermal analysis and thermogravimetric analysis methods.Öğe Synthesis of well-defined bisbenzoin end-functionalized poly(?-caprolactone) macrophotoinitiator by combination of ROP and click chemistry and its use in the synthesis of star copolymers by photoinduced free radical promoted cationic polymerization(Taylor & Francis Ltd, 2017) Uyar, Zafer; Degirmenci, Mustafa; Genli, Nasrettin; Yilmaz, AyseA new well-defined bisbenzoin group end-functionalized poly(epsilon-caprolactone) macrophotoinitiator (PCL-(PI) 2) was synthesized by combination of ring opening polymerization (ROP) and click chemistry. The ROP of epsilon-CL monomer in bulk at 110 degrees C, by means of a hydroxyl functional initiator namely, 3-cyclohexene-1-methanol in conjunction with stannous-2-ethylhexanoate, (Sn(Oct)(2)), yielded a well-defined PCL with a cyclohexene end-chain group (PCL-CH). The bromination and subsequent azidation of the cyclohexene end-chain group gave bisazido functionalized poly(epsilon-caprolactone) (PCL-(N-3)(2)). Separately, an acetylene functionalized benzoin photoinitiator (PI-alkyne) was synthesized by using benzoin and propargyl bromide. Then the click reaction between PCL-(N-3)(2) and PI-alkyne was performed by Cu(I) catalysis. The spectroscopic studies revealed that poly(epsilon-caprolactone) with bisbenzoin photoactive functional group at the chain end (PCL-(PI)(2)) with controlled chain length and low-polydispersity was obtained. This PCL-(PI)(2) macrophotoinitiator was used as a precursor in photoinduced free radical promoted cationic polymerization to synthesize an AB(2)-type miktoarm star copolymer consisting of poly(epsilon-caprolactone) (PCL, as A block) and poly(cyclohexene oxide) (PCHO, as B block), namely PCL(PCHO)(2).Öğe Thermal analysis and isoconversional kinetic study of thermal decomposition of polycyclohexene oxide polystyrene (PCHO-PST) comb-shaped polymer(Bulgarska Akademiya na Naukite, 2021) Dolaş, Hacer; Genli, NasrettinIn this study we aimed to investigate the thermal and the kinetic parameters of the thermal decomposition reaction of poly cyclohexene oxide polystyrene (PCHO-PSt) comb-shaped polymer. The polymer of epoxy end-functionalized polystyrene was synthesized by atom transfer radical polymerization (ATRP) and the glass transition of polystyrene present as a unit in the polymer was determined. The thermal characteristics of the polymer were evaluated through thermal analysis, differential thermal analysis (DTA), thermogravimetric analysis-derivative thermogravimetry (TG-DTG) under nitrogen atmosphere at 3, 5, 7 and 10 oC min-1 from 30 oC to 600 oC. The obtained results were supported by differential scanning calorimetry (DSC). The glass transition of the PCHO-PSt was seen at 79 oC. The crystallization and melting temperatures of the PCHO-PSt were determined as 142 and 240 oC, respectively. The polymer decomposition was seen in the range of 320-350 oC depending on the heating rate. Based on the isoconversional method, the activation energy was calculated by the free model approach of the Ozawa-Flynn-Wall method (OFW). The highest activation energy was found as 160.82 kJmol-1 at 30% conversion. It was found that the activation energy decreased as conversion increased.
