Browsing by Author "Yagci, Y."
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Item Open Access Electroinitiated polymerization of 2-chloroethylvinyl ether(1998) Kalaycioglu, E.; Toppare L.; Yagci, Y.The electroinitiated polymerization of 2-chloroethylvinyl ether via controlled potential conditions has been achieved. The kinetics of the polymerization were determined by cyclic voltammetry at different temperatures in dichloromethane (DM) and acetonitrile (AN). The post-polymerization kinetics were followed with a similar technique. It was found that polymerization was twice as fast in DM as in AN. In DM, both the polymerization and the post-polymerization rates increased with decreasing temperature, whereas in AN the reverse behavior was observed.Item Open Access In situ synthesis of polymer / clay nanocomposites by type II photoinitiated free radical polymerization(Wiley, 2011-08-15) Altinkok, C.; Uyar, Tamer; Tasdelen, M. A.; Yagci, Y.A new synthetic route for the preparation of poly(methyl methacrylate)/montmorillonite (PMMA/MMT) nanocomposites was reported. In this method, first 4-(dimethylamino)benzoate group was incorporated into silicate layers of clay by esterification reaction and used to produce PMMA/MMT nanocomposites by in situ Type II photoinitiated free radical polymerization. In situ photopolymerization of methyl methacrylate through into the silicate layers by either visible or UV light irradiation leads to PMMA/MMT nanocomposites. Copyright © 2011 Wiley Periodicals, Inc.Item Open Access Poly(epsilon caprolactone)/clay nanocomposites via host-guest chemistry(Elsevier Ltd, 2015) Arslan, M.; Tasdelen, M. A.; Uyar, Tamer; Yagci, Y.Cyclodextrin-modified montmorillonite (MMT-CD) has been prepared from commercial montmorillonite clay (Closite 30B) containing two hydroxyl groups by reacting succinic anhydride through esterification. Poly(epsilon caprolactone) (PCL)/clay nanocomposites are prepared by host-guest chemistry between MMT-CD as host and PCL, hydrophobic polymer as guest. The structures of the intermediates and final nanocomposite are investigated in detail by FT-IR XRD, TEM, DSC and TGA measurements. The intercalated/exfoliated morphologies are determined by combined XRD and TEM analyses. Thermal stabilities of all nanocomposites are improved by the addition of MMT-CD compared to the neat polymer. The DSC data confirm that the crystallinity of PCL is slightly increased by increasing clay loading. © 2015 Elsevier Ltd. All rights reserved.Item Open Access Polystyrene / clay nanocomposites by atom transfer radical nitroxide coupling chemistry(Wiley, 2013) Aydin, M.; Tasdelen, M. A.; Uyar, Tamer; Jockusch, S.; Turro, N. J.; Yagci, Y.An efficient protocol, atom transfer radical nitroxide coupling chemistry, for the preparation of polymer/clay nanocomposites via grafting-onto strategy with well-defined polymer, which were synthesized via atom transfer radical polymerization, has been described. The radical coupling, taking place between the clay layers, not only leads to attached polymer chains but also to successful nanocomposite formation with highly exfoliated morphology. Copyright © 2012 Wiley Periodicals, Inc.Item Open Access Polysulfone / clay nanocomposites by in situ photoinduced crosslinking polymerization(Wiley, 2011) Dizman, C.; Ates, S.; Uyar, Tamer; Tasdelen, M. A.; Torun, L.; Yagci, Y.PSU/MMT nanocomposites are prepared by dispersing MMT nanolayers in a PSU matrix via in situ photoinduced crosslinking polymerization. Intercalated methacrylate-functionalized MMT and polysulfone dimethacrylate macromonomer are synthesized independently by esterification. In situ photoinduced crosslinking of the intercalated monomer and the PSU macromonomer in the silicate layers leads to nanocomposites that are formed by individually dispersing inorganic silica nanolayers in the polymer matrix. The morphology of the nanocomposites is investigated by XRD and TEM, which suggests the random dispersion of silicate layers in the PSU matrix. TGA results confirm that the thermal stability and char yield of PSU/MMT nanocomposites increases with the increase of clay loading. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Item Open Access Self-aligned and bundled electrospun fibers prepared from blends of polystyrene (PS) and poly(methyl methacrylate) (PMMA) with a hairt-rod polyphenylene copolymer(Elsevier, 2009-07-31) Uyar, Tamer; Cianga, I.; Cianga, L.; Besenbacher, F.; Yagci, Y.Bundled and self-aligned fibers were obtained by electrospinning blends of polystyrene (PS) and poly (methyl methacrylate) (PMMA) with a hairy-rod polyphenylene-g-polystyrene/poly (a-caprolactone) (PP-g-PS/PCL) copolymer. The self-alignment and bundling characteristics of these electrospun fibers were ascribed to the unique molecular architecture of the conjugated polymer, PP-g-PS/PCL, and its interactions with the solvent and the polymer matrixes used for the electrospinning. The self-alignment and bundling was found to be much more pronounced for PP-g-PS/PCL-PS blend when compared to PP-g-PS/PCL-PMMA blend. Furthermore we found that the degree of self-alignment of the fiber bundles was enhanced by increasing the amount of PP-g-PS/PCL in the blends but the alignment completely disappeared when the solvent dimethylformamide was changed to chloroform.Item Open Access Synthesis and characterization of polysulfone / POSS hybrid networks by photoinduced crosslinking polymerization(Wiley, 2013) Dizman, C.; Uyar, Tamer; Tasdelen, M. A.; Yagci, Y.Crosslinked polysulfone/polyhedral oligomeric silsesquioxane (POSS) hybrid networks were synthesized in this work by photoinduced copolymerization of polysulfone dimethacrylate (PSU-DMA) and multifunctional POSS-methacrylamide (POSS-MAAm) with various feed ratios. The morphology of the nanocomposites was investigated by transmission electron microscopy (TEM), which suggests the random dispersion of POSS in the PSU matrix without macroscopic agglomeration. Thermogravimetric analysis results confirmed that the thermal stability and char yield of PSU-DMA/POSS-MAAm nanocomposites increased with the increase of POSS loading. Enhanced glass transition temperatures and storage modulus of the networks were observed to be higher than its precursor polymer. Polysulfone-based hybrid networks containing various POSS loadings are synthesized by photoinduced copolymerization of polysulfone dimethacrylate and multifunctional POSS-methacrylamide. While TEM results suggest the random dispersion of POSS in the polymer matrix, thermal and dynamic mechanical analyses clearly confirm the better thermal and mechanic behavior of hybrid networks. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Item Open Access Synthesis of polybenzoxazine/clay nanocomposites by in situ thermal ring-opening polymerization using intercalated monomer(2011) Demir, K.D.; Tasdelen, M.A.; Uyar, T.; Kawaguchi, A.W.; Sudo, A.; Endo, T.; Yagci, Y.A new class of polybenzoxazine/montmorillonite (PBz/MMT) nanocomposites has been prepared by the in situ polymerization of the typical fluid benzoxazine monomer, 3-pentyl-5-ol-3,4-dihydro-1,3-benzoxazine, with intercalated benzoxazine MMT clay. A pyridine-substituted benzoxazine was first synthesized and quaternized by 11-bromo-1-undecanol and then used for ion exchange reaction with sodium ions in MMT to obtain intercalated benzoxazine clay. Finally, this organomodified clay was dispersed in the fluid benzoxazine monomers at different loading degrees to conduct the in situ thermal ring-opening polymerization. Polymerization through the interlayer galleries of the clay led to the PBz/MMT nanocomposite formation. The morphologies of the nanocomposites were investigated by both X-ray diffraction and transmission electron microscopic techniques, which suggested the partially exfoliated/intercalated structures in the PBz matrix. Results of thermogravimetric analysis confirmed that the thermal stability and char yield of PBz nanocomposites increased with the increase of clay content. © 2011 Wiley Periodicals, Inc.