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  • Polymer and Materials Science  (39)
  • 1970-1974  (25)
  • 1965-1969  (14)
  • 1
    Electronic Resource
    Electronic Resource
    Interfacial polymerization of n-alkyl α-cyanoacrylate homologs (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1617-1623 
    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 n-alkyl α-cyanoacrylates from methyl through n-octyl exhibit a reverse order of polymerization rate on biological substrates compared to that on water. On water, the lower homologs spread and polymerize rapidly, whereas the higher homologs spread but polymerize slowly. On biological substrates, the lower homologs do not spread or spread slightly and the higher homologs exhibit large spreadabilities and very rapid polymerization rates. Determination of the spreading coefficients for these systems by using the monomers or model compounds confirm the observed spreadabilities. It is proposed that the increased rate of polymerization of the higher homologs on biological substrates may be due to increased catalyst concentrations on these surfaces or to the solubilization of the higher homologs at the interface, making the catalyst sites more available to the monomer. The suggestion is made that if the liquid monomers spread and orient on the substrate and subsequently polymerize, the polymers will maintain the orientation. If such is the case, a technique is available for preparing stereospecific vinyl polymers which may have different spatial configurations depending on the polarity of the liquid substrate upon which they have been allowed to spread and polymerize.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1966.070101101
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  • 2
    Electronic Resource
    Electronic Resource
    Polymer degradation. V. Changes in molecular weight distributions during sonic irradiation of polyisobuteneProd. No. 1470 (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 335-340 
    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: Gel permeation chromatography was used to follow changes in the molecular weight distribution of a polyisobutene, initial Mv = 466,000, during degradation induced by sonic irradiation. Seven samples taken at times of 200-163,500 sec. were studied. In general, a steady decrease in molecular weight was observed, although a bimodal distribution was present after 20,000 sec. irradiation. Various measures of inhomogeneity, Mw/Mn, U, etc., were examined. The function, σn/Mw, where σn is the standard deviation of the number distribution, is considered as a measure of the relative distribution. It is shown to be almost constant throughout the degradation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070110302
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  • 3
    Electronic Resource
    Electronic Resource
    Characterization of block and random ethylene-propylene copolymers by differential thermal analysisPresented in part before the Division of Polymer Chemistry, 148th National Meeting of the American Chemical Society, Chicago, August 30-September 4, 1964. (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 3061-3069 
    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: A group of C14-tagged ethylene and propylene polymers consisting of physical mixtures of homopolymers, block copolymers made up of two homopolymer sequences, and block copolymers made up of several homopolymer segments has been studied by differential thermal analysis (DTA). The effect of randomness in copolymers has also been studied in this set of systems, which contains 0-51 wt.-% ethylene. Block copolymers and physical mixtures have been found to have thermograms with endothermal minima at approximately 138 and 163°C. The ratio of heights of the two minima has been found to be a function of the ethylene and propylene content for mixtures of homopolymers and for block copolymers without randomness. DTA thus provides an analysis for monomer ratios in physical mixtures and in block copolymers of ethylene and propylene. The cooling thermograms of block copolymers have been demonstrated to have two exotherms in all cases where the block ethylene content exceeded 10%; the propylene limit was not fixed. Mixed homopolymers do not exhibit two freezing exotherms. The total heat of fusion of the polymer has been found to be a usable measure of chain randomness and block nature. The conditions for observation of single and multiple transitions have been extended.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070090912
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  • 4
    Electronic Resource
    Electronic Resource
    Progress in polymer science - Japan, Shigeharu Onogi and Keikichi Uno, Eds., Kodansha Ltd., Tokyo, Japan, and Halsted Press, New York, 1973. 302 pp. $19.50 (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 12 (1974), S. 361-362 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.130120613
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  • 5
    Electronic Resource
    Electronic Resource
    A model for gel drying (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 605-618 
    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: A theoretical model for drying of a thin gel film is presented. The model is based upon the premise that as solvent is removed from any portion of a gel structure which is permeable by the solvent, the structure shrinks locally to fill the voids left by the solvent. The diffusion coefficient of solvent through the gel film is assumed to be an exponential function of concentration and temperature. The governing equations for the model indicate that for nonisothermal drying, the results of drying and shrinkage rates are functions of 13 independent dimensionless system variables. These results are obtained with the help of a computer solution of the proposed model. The computer results indicate that, except under extreme temperature conditions, the drying and shrinkage rates are most influenced by dimensionless groups M, P, and P̄, defined by eq. (9) of the paper. Furthermore, the drying and shrinkage rates are essentially independent of groups M and P for the values of M and P greater than approximately 100 and 10, respectively. The effect of variable solvent diffusivity on approximate time to achieve the steady-state drying and shrinkage rates is approximately handled by defining a dimensionless time variable τ in terms of average solvent diffusivity. Finally, some experimental data on drying and shrinkage rates of isothermal drying of lyphogel film under natural convection condition are obtained. These data are found to be in qualitative agreement with similar computer predictions by the proposed model.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170223
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  • 6
    Electronic Resource
    Electronic Resource
    The source of degradation during extrusion of polystyrene (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 2761-2770 
    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 nature and magnitude of mechanical reactions of polystyrene in capillary flow has been examined in a model extrusion process. Studies on polystyrene quantify the sensitive increase in shear degradation tendency with increasing polymer molecular weight. A molecular weight spectrum caused by the shear stress profile was measured across the extrudate radius by the new technique of solvent coring. It was further determined that an appreciable fraction of the mechanical reaction is shear induced in the capillary reservoir. This is confirmed by precision determinations of molecular weights and distributions by gel permeation chromatography on samples taken from concentric layers in the capillary reservoir after 50% sample extrusion. These results, involving traces of oxygen as a chemical probe, describe the stress profile in the reservoir and in the capillary during the pressure extrusion of high molecular weight polystyrene. Thus, changes in molecular weight and distribution may be attributable to changes in different portions of the shear geometry rather than the uniform changes generally considered. Clear evidence is also presented showing the dramatic effects of oxygen on these shear-induced changes in molecular weight and distribution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070170913
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  • 7
    Electronic Resource
    Electronic Resource
    A mathematical model for polymerization of isoprene with n-butyllithium in hexane (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1805-1819 
    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: Isoprene was polymerized in batch reactors by use of bottle polymerization techniques at 30°, 40°, and 50°C at concentrations from 1 to 5 molar. Butyllithium concentration was varied from 0.005 to 0.03 molar. Isoprene and n-butyllithium conversions and molecular weight distributions were determined for different reaction times. Rate equations for the initiation and propagation reactions are presented. The importance of the association reactions in obtaining a narrow molecular weight distribution is illustrated.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180618
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  • 8
    Electronic Resource
    Electronic Resource
    Non-Newtonian flow and the steady-state shear compliance (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 2697-2706 
    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: A survey of viscoelastic data on amorphous polymer melts indicates that the steady-state shear compliance, Je, of many systems can be approximated from a knowledge of their flow response. For systems with monomodel molecular weight distributions, the absolute value of the reduced complex viscosity, η*/η0, is found to equal 0.67 ± 0.03 at the frequency ω, where ωη0Je = 1. This result applies to a variety of polymer systems and to a wide range of molecular weights and distributions as long as the highest molecular weight dispersion of the distribution constitutes more than 20 weight per cent of the sample. This relationship determines Je from non-Newtonian flow data and thus provides a consistent way to relate differently shaped reduced variable curves and to calculate compliances from characteristic times reported in the literature. The connection between some commonly used times and Je is given. The method of calculating Je is successfully applied to capillary measurements of melt viscosities and to characteristic times determined from steady-state shear measurements of concentrated polymer solutions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1970.070141104
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  • 9
    Electronic Resource
    Electronic Resource
    Glass transition temperatures of poly(alkyl α-cyanoacrylates) (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 3509-3514 
    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 glass transition temperatures of the poly(alkyl α-cyanocrylates) were determined by the dilatometric technique, and some of the values were checked by differential thermal analysis. The data indicate that the Tg's appear to decrease with increase in the size of the alkyl group, for a given molecular weight range. It was also found that the Tg of poly(methyl or butyl α-cyanoacrylate) increased with molecular weight. All cyanoacrylates, excepting methyl and ethyl esters, formed only low molecular weight polymers in aqueous surroundings. Therefore, they have characteristic low glass transition temperatures, causing coalescence at low temperatures.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070171122
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  • 10
    Electronic Resource
    Electronic Resource
    Compressional effects in the capillary flow of polycarbonate (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1711-1724 
    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: Recently, the characteristics for pressure corrections in capillary flow have been detailed. The apparent viscosity increases with increasing capillary shear rate for polystyrene and for poly(methyl methacrylate) have been previously explained using free volume theory. These general methods have been developed further in this work and applied to the non-Newtonian flow of a new system, the polycarbonate of bisphenol A. The pressure correction for up to 2 kilobars will be shown to linearize the capillary pressure drop versus the parameter L/D, capillary length over diameter. This correction eliminates the viscosity difference due to variations in L/D ratio. It is also observed that the zero-shear viscosity obtained by the extrapolation of the corrected capillary flow curves agrees well with new and independent data on the same polycarbonate obtained using a Weissenberg rheogoniometer. The flow data have been compared with theories and with earlier published data on the same polymer. The two sets of data are not concordant. These new and corrected shear-dependent data are, however, shown to be expressed qualitatively by the theory of Graessley, using the most probable molecular weight distribution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180611
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