Browsing by Author "Ozturk, Temel"

Now showing 1 - 6 of 6

One-Step Synthesis and Characterization of the Block-Graft Terpolymer Via Simultaneous Atom Transfer Radical Polymerization (Atrp) and Ring-Opening Polymerization (Rop) Techniques
(indian Acad Sciences, 2022) Goktas, Melahat; Aykac, Cengiz; Ozturk, Temel
In this study, we evaluated cooccurring ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) for simultaneous one-step synthesis of the block-graft terpolymer of E-caprolactone and methyl methacrylate using polyepichlorohydrin (PECH) macroinitiator. For this purpose, the block-graft terpolymer was synthesized by ROP of a lactone and ATRP of a vinyl monomer using the PECH macroinitiator, which is an initiator suitable for both ROP and ATRP in one step. Spectral and chromatographic analyzes prove that the strategy used is successful in the simultaneous one-step preparation of the block-graft terpolymer with controlled molecular weights and narrow distributions.
One-Step Synthesis of Triarm Block Copolymers by Simultaneous Atom Transfer Radical and Ring-Opening Polymerization
(Springer, 2016) Ozturk, Temel; Yavuz, Mahmut; Goktas, Melahat; Hazer, Baki
One-step synthesis of poly(MMA-b-CL) triarm block copolymers was carried out by atom transfer radical polymerization of methyl methacrylate (MMA) and ring-opening polymerization of epsilon-caprolactone (CL) using 3-chloro-1,2-propanediol trifunctional initiator. The triarm block copolymers comprising one poly-MMA arm and two poly-CL arms were synthesized by changing some polymerization conditions such as monomer/initiator concentration, polymerization time. The effect of the reactions conditions on the polydispersity and molecular weights was also investigated. The block lengths of the block copolymers were calculated by using H-1-nuclear magnetic resonance (H-1-NMR) spectrum. It was observed that the block length could be altered by varying the monomer and initiator concentrations. The characterization of the products was achieved by using H-1-NMR, Fourier-transform infrared spectroscopy, gel-permeation chromatography, differential scanning calorimetry, thermogravimetric analysis and fractional precipitation techniques.
Synthesis and Characterization of a Brush Type Graft Copolymer Via Raft and "click" Chemistry Methods
(Springer, 2023) Goktas, Melahat; Aykac, Cengiz; Ozturk, Temel
In this study, well-known poly(4-vinylbenzyl-g-ethylene glycol) [P(4-VB-g-EG)] brush type graft copolymer was synthesized by recycling additive/fragmentation chain transfer (RAFT) polymerization and a "click" chemistry method. In the first step, a RAFT agent (CTA) was synthesized for this purpose by the reaction of 2-(2-chloro ethoxy) ethanol and potassium ethyl xanthogenate salt. In the second step, poly(4-vinylbenzyl chloride) [P(4-VBC)] was synthesized by performing RAFT polymerization of 4-vinylbenzyl chloride using a RAFT initiator. In the third step, poly(4-vinylbenzyl-N-3) [P(4-VB-N-3)] was produced by a reaction that synthesized P(4-VBC)] and NaN3. In addition, PEG-propargyl (alkyne-terminated-PEG) was obtained by the reaction between polyethylene glycol (PEG-3000) and propargyl chloride. In the last step, poly(4-VB-g-EG) brush type graft copolymer was obtained by the reaction of PEG-propargyl and poly(4-VB-N-3) via the "click" chemistry method. The synthesized products were characterized utilizing various spectroscopic methods. The DSC result showed that the glass transition temperature value of the brush type graft copolymer was 30 & DEG;C, different from that of the homopolymer. The SEM analysis demonstrated that the surface morphology of the homopolymer and brush type graft copolymers differed. The fact that the brush type graft copolymer has two different decomposition temperatures such as 220 & DEG;C and 410 & DEG;C has been proven by TGA analysis.
Synthesis and Characterization of Graft Copolymers Based on Polyepichlorohydrin Via Reversible Addition-Fragmentation Chain Transfer Polymerization
(Taylor & Francis inc, 2016) Ozturk, Temel; Kaygin, Oguz; Goktas, Melahat; Hazer, Baki
In this study, synthesis of poly(epichlorohydrin-g-methyl methacrylate) graft copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization was reported. For this purpose, epichlorohydrin was polymerized by using HNO3 via cationic ring-opening mechanism. A RAFT macroinitiator (macro-RAFT agent) was obtained by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin. The graft copolymers were synthesized using macro-RAFT agent as initiator and methyl methacrylate as monomer. The synthesis of graft copolymers was conducted by changing the time of polymerization and the amount of monomer-initiator concentration that affect the RAFT polymerization. The effects of these parameters on polymerization were evaluated via various analyses. The characterization of the products was determined using H-1-nuclear magnetic resonance (H-1-NMR), Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, elemental analysis, and fractional precipitation techniques. The block lengths of the graft copolymers were calculated by using H-1-NMR spectrum. It was observed that the block length could be altered by varying the monomer and initiator concentrations.
Synthesis and Characterization of Poly(ε-Caprolactone) Tetra-Arm Star Polymer Using Tetra Terminal Alkynyl-Substituted Phthalocyanine by the Combination of Ring-Opening Polymerization and "click" Chemistry
(Ovidius Univ Press, 2022) Sava, Bedrettin; Meyvaci, Ergul; Ozturk, Temel; Agirta, Mehmet Salih
The synthesis of poly(epsilon-caprolactone) (PCL) tetra-arm star polymer was carried out using "click" chemistry and ring-opening polymerization techniques. For this purpose, poly(epsilon-caprolactone) azido (PCL-N-3) was acquired using ring-opening polymerization of epsilon-caprolactone and 2-[2-(2-azidoethoxy)ethoxy]ethanol (N(3)ol). N(3)ol was obtained using sodium azide and 2-[2-(2-chloroethoxy)ethoxy]ethanol. 4-(prop-2-ynyloxy)-phthalonitrile was obtained by using 4-nitrophthalonitrile and propargyl alcohol. 2(3),9(10),16(17),23(24) Tetrakis-[(prop-2-ynyloxy)-phthalocyaninato]zinc(II) (Pc-propargyl) was synthesized by using 4-(prop-2-ynyloxy)-phthalonitrile and a metal salt. By reacting Pc-propargyl and PCL-N-3, PCL tetra-arm star polymer was obtained by "click" chemistry. The products were characterized via scanning electron microscopy, H-1-nuclear magnetic resonance spectroscopy, ultraviolet-visible spectrophotometry, Fourier-transform infrared spectroscopy, and gel permeation chromatography instruments. The spectroscopic analyses of PCL tetra-arm star polymer prove that the star polymer was built through the combination of ROP and "click" chemistry. We provided a protocol for PCL tetra-arm star polymer, and a statement of reproducibility with respect to the properties of this tetra-arm star polymer. This study is an example of a novel type of combination reaction, from ring-opening polymerization to "click" chemistry using phthalocyanine. This can open the door for diverse tetra-arm star polymer synthesis that could potentially cause major advances in synthetic macromolecular chemistry.
Synthesis and Sensor Properties of Silicon Phthalocyanine Axially Substituted With Bis-(prop Groups and Polymeric Phthalocyanines Bearing Peg Substituent by "click" Chemistry
(Taylor & Francis Ltd, 2023) Agirtas, Mehmet Salih; Solgun, Derya Gungordu; Savas, Bedrettin; Ozturk, Temel
Synthesis and characterization of new axially substituted phthalocyanine complexes were done. Bis - (prop-2-ynyloxy) phthalocyaninato silicon (IV) compound was obtained from the reaction of 2-propin-1-ol with SiPcCl2. Polymeric phthalocyanine containing axially substituted PEG was obtained from the reaction of bis - (prop-2-ynyloxy) phthalocyaninato silicon (IV) compound and polyethylene glycol azido. The structure of the compounds was justified by FT-IR, H-1 NMR, C-13 NMR, UV-Vis, and mass spectra. The photophysical and photochemical properties of the phthalocyanine compound axially substituted with bis-(prop-2-ynyloxy) was investigated. Properties of the compounds were examined in terms of fluorescence quantum efficiency and singlet oxygen generating capacity, and the potential photosensitizer capacity of the compound was determined. In addition, polyethylene glycol group was added to the phthalocyanine compound by click reaction. The polymer product was obtained in blue color. Phthalocyanine(Pc) containing PEG polymeric units is soluble in dimethyl sulfoxide (DMSO). Absorption measurements of the compound at different concentrations were made. Both polyethylene glycol (PEG) and phthalocyanine compounds can be used in the manufacture of medical supplies due to their non-toxicity. UV-visible study of Bis-(prop-2-ynyloxy) phthalocyaninato silicon (IV) compound revealed its high selectivity for Fe3+ ion recognition.