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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 60 (1956), S. 267-269 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 18 (1988), S. 619-624 
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A novel system has been examined in which the charging cycle of a rechargeable cell was photoassisted. Rechargeable cells comprised of ap-type InP semiconductor anode coated with a polyanthraquinone redox polymer film and a polypyrrole-coated Pt cathode immersed in 0.1 M TEAP/CH3CN were photoelectrochemically charged and then discharged in the dark. These systems showed no degradation of electroactivity after 25 cycles. The charge storage capacity and the effectiveness of the photoassistance is limited by incomplete electroactivity of the redox polymer film and the small photovoltages generated by thep-InP/polyanthraquinone electrode. The role of Fermi level pinning in limiting the performance is assessed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 97-107 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Lifetimes of polymer radicals were determined by a direct flow technique. The variation of yield of polymer with the period between initiation by an ultraviolet source and destruction in an inhibitor solution was determined by spectrophotometric analysis. A swiftly falling stream of monomer was irradiated by a sharply focussed beam of intense ultraviolet radiation, and the time of radical growth was controlled by varying the distance of fall at a constant flow rate. The variation of yield of polymer with the time interval between photochemical initiation an destruction in an inhibitor solution was determined by spectrophotometric analysis of the polymer formed. A polished elliptical reflector was used, instead of the customary quartz lenses, with the source and stream at the foci of the ellipse. A water-jacketed capillary was employed to eliminate spurious thermal initiation. Radical lifetimes of 0.24 seconds for styrene and 1.80 seconds for butyl acrylate were obtained. The data were compared with values calculated on the basis of non-stationary state kinetics in a flow system.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 359-364 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Block copolymers of butyl acrylate-styrene and butyl acrylate-2-vinyl pyridine were prepared in a flow system. An intense ultraviolet source was focussed on a stream of monomer falling into a second monomer. The period between photochemical initiation in the stream and block polymer formation was controlled by varying the flow rate and distance of fall. By application of nonstationary state kinetics the yield of polymer in the stream was calculated and compared with the experimental yield determined spectrophotometrically. A comparison was made of the composition of random copolymer based on the copolymerization equation and that determined experimentally. The yields and compositions of the products showed that the desired block copolymers had been formed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 46 (1960), S. 139-149 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the polymerization of methyl methacrylate in the presence of p-benzoquinone were investigated. The course of the reaction was followed by dilatometry and with tracer methods. Alternate experiments were performed C14-tagged azobisisobutyronitrile initiator and inactive p-benzoquinone and, alternatively, radioactive initiator and inactive retarder being used. These data, coupled with number average molecular weights determined by osmometry, served to determine the number of fragments of initiator and retarder incorporated per polymer molecule. It was found that the reaction was retarded at low concentrations of p-benzoquinone but showed a definite transition to inhibition at higher concentrations. Analysis of the data showed that the number of initiator fragments incorporated per polymer molecule was independent of retarder concentration, but that the number of retarder molecules per polymer molecule increased. The results indicate that the rate of chain initiation decreases with retarder concentration until inhibition is observed. The data are interpreted on the basis of interaction of benzoquinone with primary radicals generated by the initiator. The results also furnish distinct evidence against the acceptance of copolymerization or chain transfer as significant steps in the reaction mechanism.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 817-823 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dimethylaniline (DMA) induces chain transfer in the zinc bromide-complexed donor-acceptor polymerizations of styrene-acrylonitrile to form alternating copolymers. The Mayo plots are linear, but the rates decrease with increase in DMA and degradative chain transfer occurs. Although conventional free-radical transfer agents have negligible effect on the rates or molecular weights, a twentyfold reduction of molecular weight is obtained with DMA. Spectroscopic data indicate the formation of an equimolar complex of DMA and ZnBr2, but the lowering of molecular weight is not attributable to the reduction of the effective ZnBr2, concentration. A possible mechanism involving a competition between [ZnBr2(DMA)2] and [ZnBr2,DMA,AN] is suggested.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 14 (1976), S. 2639-2647 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rate and molecular weight profiles were obtained for the spontaneous alternating copolymerizations conducted with diethylaluminum chloride. The rate formally fitted an expression, R = kp[MMA][Sty], and the rate constant was established by two distinct methods: (1) from the yield versus time data and (2) from initial rate over a range of initial concentrations; it was determined as 5.4 × 10-6 l./mole-sec with Ea = 4.2 kcal/mole. Molecular weights were determined by gel-permeation chromatography. No increase in molecular weight was observed with increased reaction time. Thus living centers or diradicals are not involved in the process. The M̄n shows a steady decrease with increase in monomer-diethylaluminum chloride concentration but the rate is maximum at equimolar monomer concentrations. The data are interpreted on a chain-transfer mechanism and show close agreement to a model in which the excess complexed acceptor monomer is the transfer agent. The chain-transfer constant of 7.1 × 10-4 l./mole-sec is several orders of magnitude greater than for uncomplexed systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 1957-1966 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A technique has been developed for initiating a graft copolymerization electrochemically. A copoly(styrene/vinylbenzophenone) linear copolymer was prepared to serve as the electroactive starting material. The benzophenone sites on this molecule are readily activated at the cathode. Macroradical ions result from the direct transfer of electrons to benzophenone groups of the electroactive backbone polymer. In solution in N,N-dimethylformamide with tetraethylammonium perchlorate (TEAP) as supporting electrolyte the passage of current produced a dark blue solution similar to that observed with radical anions obtained with benzophenone directly. When monomer such as acrylonitrile or methyl methacrylate was added, a graft copolymer was formed. Electrolysis of solutions of the backbone polymer in tetrahydrofurn (THF), with sodium tetraphenylboride as supporting electrolyte, produced relatively stable, persistent macroradical anions and, under appropriate conditions, the reddish-violet macrodianions. Both types initiated graft copolymerization of acrylonitrile and methyl methacrylate. Graft copolymers were characterized by gel permeation chromatography (GPC), infrared (IR), and solvent extraction. High grafting efficiency (i. e., free from homopolymer) can be obtained under appropriate conditions. Suitable mechanisms are proposed, compared, and discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 203-211 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the electrochemical reduction of an electroactive polymer several thousand electrons may be transferred to a single molecule. For polymers with noninteracting centers, recently developed theory indicates that the current - potential response would be identical with that of the corresponding molecule solvation, structural change, and variation in ionic environment, and may be used to probe these factors. A series of model compound of poly(vinylbenzophenone) and of poly(vinylbenzophenone-co-styrene) were prepared and investigated. In this study samples of various constant chain length with differing spacing of electroactive centers were employed. The current - potential measurements corresponded to the ideal theoretical case. This indicates that the behavior of the electroactive groups attached to the polymer chain was not influenced by the macromolecular environment or by neighboring group interaction.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 13 (1975), S. 501-504 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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