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Hyperbranched Structure (hyperbranched + structure)
Selected AbstractsA Hyperbranched, Highly Deliquescent Polymer,ADVANCED MATERIALS, Issue 24 2007L. Tian Atom transfer radical polymerization is used to prepare a highly deliquescent hyperbranched polymer from a monomer containing polymerizable vinyl group and an initiation-ready site for branching and chain growth, as depicted in the figure. The figure also shows the very rapid deliquescence kinetics of this polymer originating from its hyperbranched structure. [source] Synthesis of hyperbranched polymers with precise conjugation lengthJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2007Jing Li Abstract A set of AB2 type monodisperse conjugated oligomers carrying two bromo functional groups and one boronic ester functional group were prepared by iterative deprotection and Sonogashira cross-coupling reactions. Suzuki polycondensation of these AB2 type monodisperse oligomers afforded hyperbranched polymers. The hyperbranched conjugated polymers we prepared possess not only precisely controlled conjugation length like monodisperse conjugated oligomers but also the structural feature of hyperbranched polymers. Optical property investigation demonstrated that the maximum absorption and emission wavelength red-shifted along with the increasing of the conjugation length between the two branching points and the hyperbranched structure could effectively reduce the aggregation of the conjugated polymer chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1084,1092, 2007 [source] New Second-Order Nonlinear Optical Polymers Derived from AB2 and AB Monomers via Sonogashira Coupling ReactionMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 8 2010Zhong'an Li Abstract In this paper, a facile route was designed to prepare a new AB2 -type polymer P1 via simple Sonogashira coupling reaction, also its corresponding linear analog (P2) was obtained from AB monomer for comparison. Despite the relatively lower loading density of the effective chromophore moieties, P1 demonstrated higher second-harmonic coefficient (153.9,pm,·,V,1) than that of P2 (98.2,pm,·,V,1), due to the three-dimensional spatial isolation effect of the hyperbranched structure. The good results of P2 also indicated that the ladder shape may help to solve the problem existing in main-chain polymers, the low poling efficiency. [source] Hyperbranched Polyalkoxysiloxanes via AB3 -Type MonomersMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 7 2003Manfred Jaumann Abstract We have synthesized polyethoxysiloxanes starting from the AB3 -type monomers triethoxysilanol and acetoxytriethoxysilane. The polymers are liquid and soluble in organic solvents. 29Si NMR spectroscopy and MALDI-ToF mass spectrometry analyses show that the polymers have a hyperbranched structure with additional internal cyclization. 29Si NMR spectroscopy indicates that the polymer synthesized from acetoxytriethoxysilane is less branched than the polymer synthesized from triethoxysilanol. Analysis of the molar mass and mass distribution of the polymers via size exclusion chromatography (calibrated via MALDI-ToF MS and viscosimetry) yields a molar mass of Mn,,,2 kg,·,mol,1 and Mw,,,8 kg,·,mol,1 for polymers synthesized from triethoxysilanol. The molar mass of the polymers synthesized from acetoxytriethoxysilane can be controlled by variation of the polymerization time in the range of Mn,,,1.8,12 kg,·,mol,1 and Mw,,,2.1,2,200 kg,·,mol,1. Photograph of a vial containing polyethoxysiloxane obtained from triethoxysilanol and a schematic drawing of the proposed molecular structure of the polymer. [source] | ||||||||||