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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of a diphenylethylene derivative carrying aromatic tertiary amine groups and its use in chain end functionalization of alkyllithium-initiated polymerizations (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 2185-2191 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1,1-Bis[(4-dimethylamino)phenyl]ethylene was successfully synthesized through the ‘Wittigtype’ reaction of 4,4′-bis(dimethylamino)benzophenone with the ‘Tebbe’ reagent. The methylenation yields were over 80 wt.-% on the basis of the initial amount of benzophenone derivative used. Terminally functionalized polymers having aromatic tertiary amine groups at one end or at both ends were prepared by the crossover reactions of n-butyllithium (n-BuLi), poly(styryl)lithium (PSLi), and poly(isoprenyl)lithium (PILi) with the diphenylethylene analogue. The functionalization yields were over 87 mol.-% based on the results of 1H NMR spectroscopic analysis. The number-average molecular weights of the polymers based on the ratio [gram of monomer]/[mole of initiator] are in good accordance with those observed from size exclusion chromatographic and 1H NMR spectroscopic analysis (3,0 × 103 ∼ 7,5 × 103 g/mol).
    Additional Material: 7 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of activities of homogeneous Ti-based catalysts in the presence of methylaluminoxane (MAO) for synthesis of syndiotactic polystyrene by UV/visible spectroscopic study (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1733-1741 
    Details
    ISSN: 0887-624X
    Keywords: homogeneous Ti-based catalyst ; methylaluminoxane ; catalytic activity ; UV/visible spectroscopy ; syndiotactic polystyrene ; polymorphic structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The catalytic activities in syndiospecific polymerization of styrene in hydrocarbon using homogeneous Ti-based catalysts in the presence of methylaluminoxane (MAO) were investigated through UV/visible spectroscopic analysis. A strong UV absorption band of CpTiCl3, itself, incipiently appeared at λmax = 400 nm in toluene, followed by a bathochromic shift with its remarkable decrease by the addition of MAO. The absorption band intensity at λmax = 400 nm arising from delocalization of π-electrons on the cyclopentadienyl ring decreased by methylation in the presence of MAO with regard to the mechanism for production of an active center (“cation-like”), for example, the change of the ionic nature. The intensity decrease at λmax = 400 nm was suppressed over 2000 of the [Al]/[Ti] ratio. In the case of Ti(OC4H9)4 having a σ-ligand, new and broad UV absorption bands were developed at λmax = 340 nm and 410 nm in the presence of MAO in contrast with the CpTiCl3/MAO system. Comparison between the relative absorption intensities at λmax = 340 nm and 410 nm led to the determination of a maximum catalytic activity of Ti(OC4H9)4 in the presence of MAO related to the polymerization yield. The maximum polymerization yield was observed with regard to the relative maximum value of the absorption intensity at λmax = 410 nm with the [Al]/[Ti] ratio (500). From observation for polymorphism of the final products via differential scanning calorimetric analysis (DSC), the thermally unstable β-form seemed to be produced by the CpTiCl3/MAO system independent of the MAO concentration, the Ti(OC4H9)4/MAO system produced a thermally stable α-form in the low MAO concentration (up to 100 of the [Al]/[Ti] ratio), and a mixture of α- and/or β-forms over 200 of the [Al]/[Ti] ratio under our experimental conditions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1733-1741, 1998
    Additional Material: 9 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Microstructure effect in the coupling reactions of polymeric organolithium compounds using chlorosilanes (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1743-1753 
    Details
    ISSN: 0887-624X
    Keywords: coupling reaction ; living polymer ; microstructure ; coupling yield ; 1,4-enchainment ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The most important variable affecting the yield in the coupling reactions of polymeric organolithium compounds with chlorosilane compounds has been investigated through size-exclusion chromatographic (SEC) analysis. The coupling reaction of poly(styryl)lithium with dichlorodimethylsilane as a silane-coupling agent provided 44 wt % of the coupling yield. The coupling yield, depending on the chain end reactivity of active polymers, was not greatly affected. The addition of a Lewis base such as N,N,N′,N′-tetramethylethylenediamine (TMEDA) even after complete polymerization of the dienes in hydrocarbon seems to affect the coupling reaction, resulting in decreasing the yield. The 1,2- or 3,4-enchain contents in the polydiene backbones affected the reduction of the linking efficiency in the coupling of the poly(dienyl)lithiums with chlorosilanes as the linking agent. The linking yields of the active polymers including over 75 mol % of 1,2- or 3,4-enchainment on the polydiene segment were below 20 wt %. The linking yields exhibited a dependence not only on the steric requirement of the chain end, but also the microstructure of the polydiene segment. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1743-1753, 1998
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Blue and green light emission from new soluble alternating copolymers (1997)
    Weinheim : Wiley-Blackwell
    Advanced Materials 9 (1997), S. 326-328 
    Details
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19970090408
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  • 5
    Electronic Resource
    Electronic Resource
    Morphological features of blown high-density polyethylene films (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1717-1729 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The blown films of high-density polyethylenes with unimodal and bimodal molecular weight distribution were prepared under several processing conditions, and their morphologies were extensively characterized. The high molecular weight tail (MW 〉 ∼ 106) of the molecular weight distribution seems to play a critical role on the morphology of blown highdensity polyethylene films irrespective of the molecular weight distribution mode of the resins. As the content of high molecular weight species increased, the tendency for high stress-crystallization increased and the network structure of lamellar stacks was better developed. The intercrystalline connectivity along the normal direction of lamellar stacks was higher than that along the transverse direction of lamellar stacks. © 1996 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Short chain branching distribution and thermal behavior of high density polyethylene (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 2469-2479 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: High-density polyethylenes with unimodal and bimodal molecular weight distribution have been fractionated according to crystallizability using preparative temperature rising elution fractionation. The molecular structure and thermal properties of the fractions with their whole polymers have been characterized. The average short chain branching content of the fractions obtained ranged from 0 to 8 branches per 1000 carbon atoms while that of the whole polymers is about 2 branches per 1000 carbon atoms. The bimodal resins have a slightly higher frequency of short chain branch in higher molecular weight species than in those of the unimodal resins. The short chain branching distribution as well as the low molecular weight species in the fractions seem to be important parameters to determine thermal behavior of the fractions. The fractions with the short chain branching content above 3 branches per 1000 carbon atoms showed a significantly different thermal behavior from those with less than 3 branches per 1000 carbon atoms. © 1996 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Copolymer composition-dependent light transmission of polymer/liquid crystals composite films (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 55-64 
    Details
    ISSN: 0887-6266
    Keywords: PDLC ; polarization ; angular discrimination ; copolymer ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Electrooptic responses (voltage and angular-dependent transmittance) of polymer/liquid crystal composite films with H, V, and unpolarized lights have been studied based on a nematic liquid crystal (Ro-5921) and four types of homopolymers and copolymers from ethyl methacrylate and styrene with different compositions. In this way, the index ratio of the polymer (np) to the ordinary refractive index of liquid crystal (no)(np/no) has been varied systematically, and the effect of the index ratio on viewing angle, applied voltage, response times, and transient response have been investigated. With increasing styrene content in the copolymer, droplet size increased, threshold (Vth) and saturation (Vsat) voltage, and rise time decreased. With np ≲ no, maximum transmittance occurred at normal incidence, regardless of the type of polarization. On the contrary with np 〉 no, V-polarization gave a peak in the transmittance-voltage curve, and transmittance overshot upon removal of the field, and these were interpreted in terms of effective refractive index and two-step relaxations. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 55-64, 1998
    Additional Material: 10 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Water soluble, conjugated main chain azo polymer: Synthesis and characterization (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 17 (1996), S. 853-857 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The monomer 2,5-diaminobenzenesulfonic acid has been polymerized to a high molecular weight, conjugated main chain azo polymer. The presence of the azo group in the polymer was confirmed using Raman spectroscopy. The polymer is highly soluble in water over a wide pH range. It is also soluble in common polar organic solvents such as N,N-dimethylformamide, dimethyl sulfoxide and N-methyl-2-pyrrolidone.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1996.030171202
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  • 9
    Electronic Resource
    Electronic Resource
    XPS sputter depth profiling of the chemical states for SrTiO3/Si interface by O2+ ion beams (1995)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 23 (1995), S. 851-857 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Because the chemical states of the elements in SrTiO3 thin film on Si are reduced by argon ion beam bombardment, it was impossible to sputter depth profile the chemical states of SrTiO3 thin film by argon ion beams. In this paper, it is reported that the undistorted chemical states of Ti and Si at the SrTiO3/Si interface can be determined with oxygen ion beams at the appropriate 70° angle of incidence, with which either metallic Ti is not oxidized or Ti in SrTiO3 is not reduced. Under the sputter depth profiling conditions, the chemical state of Ti at the SrTiO3/Si interface could be successfully characterized and the effects of post-annealing at high temperature on the chemical state of Ti were studied. A significant number of Ti atoms in the metallic state were observed at the SrTiO3/Si interface without any post-annealing but all of them were oxidized to the Ti4+ chemical state after 2 h post-annealing at the temperatures above 600°C under oxygen flow. The dielectric properties of SrTiO3 thin films on Si were well correlated to the oxidation state of Ti and the broadening of the interface SiO2 layer induced by post-annealing at high temperature.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740231302
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  • 10
    Electronic Resource
    Electronic Resource
    Organo-soluble aromatic polyamide filmsPresented at ‘MacroAkron '94, 35th IUPAC Symposium on Macromolecules’, Akron, Ohio, 11-15 July 1994. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 36 (1995), S. 203-211 
    Details
    ISSN: 0959-8103
    Keywords: aramid ; isotropic solution ; film ; high strength ; high modulus ; fibrillation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: To make stable isotropic aramid solutions and films, 6-amino-2-(4-aminopheyl)-4-phenyl quinoline (QDA) was used as base diamine, and copolymerized using terephthaloyl chloride (TPC) with p-phenylene diamine (PPD), 2,2′-bis(trifluoromethyl)benzidine (PFMB), and oxydianiline (ODA) as second diamine, respectively. Homogeneous viscous polymerization solutions based on QDA were obtained, and films prepared from them were transparent and amorphous. The reactivity of QDA with TPC was almost equal to that of PPD; the reactivity of PFMB was low due to the electron withdrawing groups (—CF3) attached to the ortho positions of the benzene rings. Bulkiness and flexibility of the monomer structure widened the of stable conditions in polymer solution. A rod-like structure of the monomer caused drawbility to decrease. QDA/ODA copolymer films could be drawn well, probably as a result of the flexible linkage of ODA, and had high tensile strength (86 kg/mm2). High modulus, 3.1 × 103 kg/mm2, was obtained in QDA/PPD copolymer films. Tensile strength and modulus increased with draw ratio. Tg and Tm were not seen by DSC and Td of the polymers was as high as c. 500°C. Excess drawing caused the films to be fibrillated, affecting their tensile properties.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210360211
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