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101.
Summary: Polybenzoxazines are newly developed thermosetting polymers exhibiting versatility in a wide range of applications including electronics and aerospace industries. They exhibit highly competitive combination of properties compare to the conventional thermosets. In this paper we present synthetic strategies to incorporate thermally curable benzoxazine functions into polymers as main and side chain groups in order to further improve various properties. The strategies successfully employed include monomer synthesis, macromonomer method, polycondensation, oxidative polymerization, photo-polymerization, click chemistry and hydrosilylation processes. In the case of macromononomer method functional initiators were used in various controlled/living polymerizations to give polymers with benzoxazine end groups. The thermal curing behaviors of the obtained polymers were also demonstrated. 相似文献
102.
Zeynep Beyazkilic Muhammet U. Kahveci Binnur Aydogan Baris Kiskan Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):4029-4036
A new class of polybenzoxazine precursors of combined molecular structure of benzoxazine in the open and ring form has been developed. Thermally curable benzoxazine networks were obtained by simultaneous photoinduced thiol‐ene and Catalytic Opening of the Lateral Benzoxazine Rings by Thiols (COLBERT). The thiol‐ene reactions were initiated by photolysis of a free radical photoinitiator, 2, 2‐dimethoxy‐2‐phenyl acetophenone (DMPA), and the competing COLBERT reaction was triggered by thiol compound, 1,2‐ethanedithiol, present in the reaction mixture. The extent of reactions was evaluated by conducting experiments both under UV irradiation and in dark using model benzoxazines. The precursor soft films (pre‐P(B‐ala‐DTE)) were prepared by irradiating solutions of diallyl functional benzoxazine (B‐ala), 1,2‐ethanedithiol and DMPA. The obtained pre‐P(B‐ala‐DTE) films were then cured through thermally activated ring opening reaction of remaining benzoxazine groups yielding a more rigid and tough film. Thermal and mechanical properties of the films were investigated by DSC, DMA and TGA and compared with a typical polybenzoxazine, P(B‐ala). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
103.
Baris Coskunuzer 《Journal of Geometric Analysis》2017,27(2):1211-1236
We show that any open orientable surface can be properly embedded in \(\mathbb {H}^3\) as a constant mean curvature H-surface for \(H\in [0,1)\). We obtain this result by proving a version of the bridge principle at infinity for H-surfaces. We also show that any open orientable surface can be nonproperly embedded in \(\mathbb {H}^3\) as a minimal surface. 相似文献
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108.
Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 41, No. 12, pp.1607–1613, December, 1989. 相似文献
109.
A squarate-based synthesis of ferrocenyl quinones is described. Thermolysis of ferrocenyl-substituted cyclobutenones, prepared from ferrocenyl cyclobutenediones and alkenyllithiums, affords hydroquinones, which furnish, upon oxidation, ferrocenyl quinones. Ferrocenyl cyclobutenediones have been prepared from known cyclobutenediones by nucleophilic addition of ferrocenyllithium followed by hydrolysis, Pd/Cu-cocatalyzed cross-coupling with (tri-n-butylstannyl)ferrocene or Friedel-Crafts alkylation with ferrocene. 相似文献
110.
Baris Temelli 《Tetrahedron letters》2005,46(46):7941-7943
The Cu(OTf)2 catalysed reaction of pyrrole with N-tosyl imines gives pyrrole sulfonamides in high yields. The addition reaction takes place regioselectively at C(2) of the pyrrole. The procedure is simple and does not require anhydrous conditions. 相似文献