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  • 1
    Electronic Resource
    Electronic Resource
    Application of transmission Mössbauer spectroscopy to the surface study of Ni(II)-Fe(III) hydroxide electrocatalysts: Comparison with AES data (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 20 (1993), S. 949-954 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Transmission Móssbauer spectra of binary coprecipitated nickel(II)-iron(III) hydroxides (molar ratios 9:1 and 4:1) are analysed and compared with the results of AES analyses of their surface composition. A correlation between the data of the above techniques has been noted, indicating a redistribution of the components (i.e. Ni and Fe) in the surface layers, the latter being enriched with iron(III) as compared to the bulk. The results obtained are in good agreement with an excellent electrocatalytic activity of composite Ni-Fe hydroxide systems towards anodic oxygen evolution in alkaline electrolytes, taking into account a distinctly exhibited ‘surface’ electrocatalytic effect of ferric species on the nickel hydroxide electrode in the anodic oxygen evolution process revealed previously. Transmission Móssbauer spectroscopy has been shown to be a highly effective probe sensitive both to various bulk and surface effects related to the solid phases studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740201204
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  • 2
    Electronic Resource
    Electronic Resource
    Diene polymerization by mixed sodium- and lithiumalkyl initiators in hydrocarbon medium (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 375-383 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of butadiene and isoprene initiated by the hydrocarbon-soluble mixture 2-ethylhexyllithium/2-ethylhexylsodium in toluene was studied. The components of the initiator when taken separately give rise to polymers greatly different in both their molecular weight and microstructure: living polydienes with high 1,4-unit content are formed when alkyllithium is used while organosodium initiators produce polymers of high 1,2(3,4)-structure and of low molecular weight due to strong chain transfer to toluene. Polymers obtained with mixed initiators were found to have the same structure as the “sodium” ones, while their molecular weights are either the same as those of the polymers obtained with alkyllithium alone (in the case of butadiene) or decrease gradually with increase of sodium content in the initiator (in the case of isoprene). The calculations performed show that the simple scheme assuming chain propagation through individual lithium and sodium active centres and fast exchange of counter-ions between them cannot explain the results obtained. It is suggested that the true active centres in mixed systems are bimetallic complexes containing both sodium and lithium atoms simultaneously.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021960127
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  • 3
    Electronic Resource
    Electronic Resource
    Investigation of the initiation reaction of isoprene polymerization with 2-ethylhexylsodium in heptane (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 3855-3861 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the initiation of isoprene polymerization in heptane with the hydrocarbon-soluble alkylsodium compound 2-ethylhexylsodium was studied. Initiation rates were estimated from the induction period and by measuring UV spectra of polyisoprenyl-sodium (λmax = 304 nm) during the course of polymerization. The initiation reaction is first order in initiator both in the course of the reaction and with respect to the starting concentration of the initiator. The same result is obtained when 2-ethylhexyllithium is used. The initiation rate constants are: ki = 1,6 · 10-3 and 5,5 · 10-4 L/(mol · s) for sodium and lithium compounds at 26°C, respectively. Aggregated forms of organoalkali compounds are suggested to take part in the initiation reaction of isoprene polymerization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021981207
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetics of isoprene polymerization in the presence of 2-ethylhexylsodium and its mixtures with 2-ethylhexyllithium in hydrocarbon solvents (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1025-1028 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The anionic polymerization of isoprene with 2-ethylhexylsodium soluble in hydrocarbons in the absence of electron donor additives has been studied. The kinetics of the propagation reaction is shown to strongly depend on the solvent used. In toluene, the reaction order in initiator appears to be fractional, its value being dependent on the initiator concentration, while in heptane the first order is known to be followed. For polymerization in toluene, a scheme is suggested where monomeric and tetrameric active species are supposed to take part in propagation. With a non-linear regression fit, apparent constants in the equation describing this scheme were evaluated. The kinetics of isoprene polymerization with the mixed 2-ethylhexylsodium/2-ethylhexyllithium initiator, as well as UV spectra of the living polymers obtained, were also studied. Formation of complex active species is suggested.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Monolayers of isotactic polypropylene oxide (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 455-456 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1202811733
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  • 6
    Electronic Resource
    Electronic Resource
    Application of transmission Mössbauer effect spectroscopy to the study of electrocatalysis and adsorption phenomena at the nickel hydroxide electrode (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 19 (1992), S. 577-580 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Mössbauer parameters for ferric hydroxo forms in alkaline matrices, ferric oxyhydroxide and its admixture at the nickel hydroxide electrode surface as well as for ferric hydroxo species absorbed at nickel hydroxides from strongly alkaline solutions have been compared. The feasibility of transmission Mössbauer spectra acquisition for the adsorbed species in the presence of dissolved forms (e.g. in situ) is based on the principle that the latter give no Mössbauer effect at room temperature owing to their diffusional mobility, while the former, being fixed at the adsorbent surface, have been shown to exhibit a sufficient resonant absorption. The effects of adsorption and water have been noted. Some questions connected with anodic oxygen evolution electrocatalysis by iron species involved in the anodic process at the nickel hydroxide electrode are also discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.7401901107
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  • 7
    Electronic Resource
    Electronic Resource
    Buried surface area, conformational entropy, and protein stability (1984)
    New York : Wiley-Blackwell
    Biopolymers 23 (1984), S. 1605-1620 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper, how to calculate the loss of conformational entropy owing to protein folding from data on protein stability, the disulfide bonding pattern and the buried surface area is suggested. The average values of the initiation constant and entropy loss per residue for the helix-coil transition, calculated according to the suggested approach, are in a good agreement with available data. It is shown that the loss of conformational entropy for proteins and protein fragments, thus calculated, can be quite accurately approximated by three straight lines, each representing the loss of conformational entropy in a given range of molecular weights. The first line corresponds to the formation of α helices, the second to proteins with molecular weights below 10,000, and the third to proteins with molecular weights above this value. The standard error varied from 1.3 kcal/mol, for the first region, to between ∼3 and 5 kcal/mol for the third. Use of these approximating linear functions is proposed for the calculation of protein stabilities from x-ray data. Such calculations, performed for more than 20 proteins and their fragments, have led to at least qualitative agreement between the calculated stabilities and available data for more than 90% of the cases. While quantitative predictions are at the limit of the method's accuracy, predictions of the probabilities of proteins or their fragments to be stable are expected to give a correct answer in ∼95% of the cases.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360230813
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  • 8
    Electronic Resource
    Electronic Resource
    Polymerization of conjugated dienes initiated by soluble organosodium compounds in hydrocarbon solventsPresented at ‘MacroAkron '94, 35th IUPAC Symposium on Macromolecules’, Akron, Ohio, 11-15 July 1994. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 37 (1995), S. 165-169 
    Details
    ISSN: 0959-8103
    Keywords: anionic polymerization ; chain transfer ; organosodium initiators ; kinetics ; butadiene ; isoprene ; 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: Polymerization of butadiene and isoprene in hydrocarbon solvents initiated by unsolvated organosodium compounds was studied. It was found that the polymer molecular weight and the MWD are determined mainly by chain transfer to solvent and polymer, and no chain transfer to monomer was observed even in the case of isoprene. The overall polymerization rate is proportional to the concentrations of the monomer and the initiator. Apparent chain propagation rate constants were found to be 0.11 litre mol-1 s-1 for butadiene and 0.065 litre mol-1 s-1 for isoprene polymerization in heptane at 30°C. It is suggested that associated (dimeric) forms of polydienylsodium active centres play an important role in chain propagation, being responsible for a stronger chain transfer and a greater 1,2-butadiene, or 3,4-isoprene, unit content than in polymerization with other alkali metals.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1995.210370303
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  • 9
    Electronic Resource
    Electronic Resource
    Polymerization of vinyl acetate in aqueous media. Part II. The kinetic behavior in the presence of low concentrations of added soaps (1962)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 61 (1962), S. 127-133 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of adding low concentrations of the three different types of soaps on the heterogeneous polymerization of vinyl acetate in aqueous solution, with K2S2O8 as initiator, has been studied. Neutral soaps produced no appreciable effect on the polymerization rate, whereas anionic soap increased the rate, the magnitude of the increase being affected by the length of the paraffin chain in the anion. Cationic soaps decreased the rate of polymerization in the early stages of the reaction, but in this case the length of the paraffin chain in the cation had no influence. The results have been interpreted in terms of the adsorption of the soap onto the surface of the small polymer particles, and the resultant reduction or promotion of the coalescence of these small particles.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1962.1206117116
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  • 10
    Electronic Resource
    Electronic Resource
    Some remarks to the kinetics of anionic polymerization of ethylene oxide in dimethyl sulfoxide (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 969-973 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of ethylene oxide (EO) polymerization in dimethyl sulfoxide with potassium tert-butoxide as initiator at 323, 333, and 343 K has been studied. The process follows the first order with respect to initiator in the concentration range 1,5-5,9 · 10-3 mol · dm-3 and the rates are the same as in the polymerization of EO with dimsylpotassium (potassium methylsulfinylmethanide). It is supposed that the tert-butoxide and dimsyl anions are equally effective as initiators and their ionization equilibrium does not affect the polymerization rate. The above conclusion agrees well with the very slow chain transfer to dimethyl sulfoxide in the anionic polymerization of EO.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790411
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