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High-molecular-weight Poly (high-molecular-weight + poly)
Selected AbstractsHigh-Molecular-Weight Poly(vinylphosphonate)s by Single-Component Living Polymerization Initiated by Rare-Earth-Metal Complexes,ANGEWANDTE CHEMIE, Issue 20 2010Übertragbar: Auf einem Gruppentransferpolymerisations(GTP)-Mechanismus beruht die lebende Polymerisation von Diethylvinylphosphonat zu Homo- und Copolymeren mit hohen Molekulargewichten in Gegenwart einfacher Seltenerdmetall-Komplexe (siehe Schema). Dieser Mechanismus, der dem etablierten Mechanismus für polare Monomere wie Acrylate entspricht, öffnet einen neuen Zugang zu phosphorhaltigen Polymeren. [source] Synthesis and characterization of phthalazinone containing poly(arylene ether)s via a novel N,C coupling reactionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2003S. J. Wang Abstract High-molecular-weight poly(phthalazinone)s with very high glass-transition temperatures (Tg's) were synthesized via a novel N,C coupling reaction. New bisphthalazinone monomers (7a,e) were synthesized from 2-(4-chlorobenzoyl) phthalic acid in two steps. Poly(phthalazinone)s, having inherent viscosities in the range of 0.34,0.91 dL/g, were prepared by the reaction of the bis(phthalazinone) monomers with an activated aryl halide in a dipolar aprotic solvent in the presence of potassium carbonate. The poly(phthalazinone)s exhibited Tg's greater than 230 °C. polymer 8b synthesized from diphenyl biphenol and bis(4-flurophenyl) sulfone demonstrated the highest Tg of 297 °C. Thermal stabilities of the poly(phthalazinone)s were determined by thermogravimetric analysis. All the poly(phthalazinone)s showed a similar pattern of decomposition with no weight loss below 450 °C in nitrogen. The temperatures of 5% weight loss were observed to be about 500 °C. The poly(phthalazinone)s containing 4,4,-isopropylidenediphenol and 4,4,-(hexafluoroisopropylidene) diphenol and diphenyl ether linkage were soluble in chlorinated solvents such as chloroform. Other poly-(phthalazinone)s were soluble in dipolar aprotic solvents such as N,N,-dimethylacetamide. The soluble poly(phthalazinone)s can be cast as flexible films from solution. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2481,2490, 2003 [source] Poly(triarylamine): Its synthesis, properties, and blend with polyfluorene for white-light electroluminescenceJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2007Hung-Yi Lin Abstract A new high-molecular-weight poly(triarylamine), poly[di(1-naphthyl)-4-anisylamine] (PDNAA), was successfully synthesized by oxidative coupling polymerization from di(1-naphthyl)-4-anisylamine (DNAA) with FeCl3 as an oxidant. PDNAA was readily soluble in common organic solvents and could be processed into freestanding films with high thermal decomposition and softening temperatures. Cyclic voltammograms of DNAA and PDNAA exhibited reversible oxidative redox couples at the potentials of 0.85 and 0.85 V, respectively, because of the oxidation of the main-chain triarylamine unit. This suggested that PDNAA is a hole-transporting material with an estimated HOMO level of 5.19 eV. The absorption maximum of a PDNAA film appeared at 370 nm, with an estimated band gap of 2.86 eV from the absorption edge. Unusual multiple photoluminescence maxima were observed at 546 nm, and this suggested its potential application in white-light-emission devices. Nearly white-light-emission devices could be obtained with either a bilayer-structure approach {indium tin oxide/poly(ethylenedioxythiophene):poly(styrene sulfonate)/PDNAA/poly[2,7-(9,9-dihexylfluorene)] (PF)/Ca} or a polymer-blend approach (PF/PDNAA = 95:5). The luminance yield and maximum external quantum efficiency of the light-emitting diode with the PF/PDNAA blend as the emissive layer were 1.29 cd/A and 0.71%, respectively, and were significantly higher than those of the homopolymer. This study suggests that the PDNAA is a versatile material for electronic and optoelectronic applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1727,1736, 2007 [source] Acyclic diene metathesis polymerization of 2,5-dialkyl-1,4-divinylbenzene with molybdenum or ruthenium catalysts: Factors affecting the precise synthesis of defect-free, high-molecular-weight trans -poly(p -phenylene vinylene)sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2005Kotohiro Nomura Abstract Factors affecting the syntheses of high-molecular-weight poly(2,5-dialkyl-1,4-phenylene vinylene) by the acyclic diene metathesis polymerization of 2,5-dialkyl-1,4-divinylbenzenes [alkyl = n -octyl (2) and 2-ethylhexyl (3)] with a molybdenum or ruthenium catalyst were explored. The polymerizations of 2 by Mo(N -2,6-Me2C6H3) (CHMe2 Ph)[OCMe(CF3)2]2 at 25 °C was completed with both a high initial monomer concentration and reduced pressure, affording poly(p -phenylene vinylene)s with low polydispersity index values (number-average molecular weight = 3.3,3.65 × 103 by gel permeation chromatography vs polystyrene standards, weight-average molecular weight/number-average molecular weight = 1.1,1.2), but the polymerization of 3 was not completed under the same conditions. The synthesis of structurally regular (all- trans), defect-free, high-molecular-weight 2-ethylhexyl substituted poly(p -phenylene vinylene)s [poly3; degree of monomer repeating unit (DPn) = ca. 16,70 by 1H NMR] with unimodal molecular weight distributions (number-average molecular weight = 8.30,36.3 × 103 by gel permeation chromatography, weight-average molecular weight/number-average molecular weight = 1.6,2.1) and with defined polymer chain ends (as a vinyl group, CHCH2) was achieved when Ru(CHPh)(Cl)2(IMesH2)(PCy3) or Ru(CH-2-OiPr-C6H4)(Cl)2(IMesH2) [IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene] was employed as a catalyst at 50 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6166,6177, 2005 [source] The Formation of Ordered Nanoholes in Binary, Chemically Similar, Symmetric Diblock Copolymer Blend Films,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 12 2004Yu Xuan Abstract Summary: Binary symmetric diblock copolymer blends, that is, low-molecular-weight poly(styrene- block -methyl methacrylate) (PS- b -PMMA) and high-molecular-weight poly(styrene- block -methacrylate) (PS- b -PMA), self-assemble on silicon substrates to form structures with highly ordered nanoholes in thin films. As a result of the chemically similar structure of the PMA and the PMMA block, the PMMA chain penetrates through the large PMA block that absorbs preferentially on the polar silicon substrate. This results in the formation of nanoholes in the PS continuous matrix. An atomic force microscopy image of the thin film obtained from the blend of low-molecular-weight PS- b -PMMA and high-molecular-weight PS- b -PMA. The regular array of nanoholes in the films surface is clearly visible. [source] | ||||||||||