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  • 1
    Electronic Resource
    Electronic Resource
    Diffusion of methyl ethyl ketone in polyisobutylene: Comparison of spectroscopic and gravimetric techniques (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1261-1267 
    Details
    ISSN: 0887-6266
    Keywords: FTIR-ATR spectroscopy ; gravimetric sorption ; diffusion ; polymer ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this study, vapor sorption FTIR-ATR (Fourier Transform Infrared Attenuated Total Reflectance) spectroscopy was combined with a conventional gravimetric sorption balance to examine diffusion in polymers. Mutual diffusion coefficients of methyl ethyl ketone in polyisobutylene were measured using both methods at various penetrant activities and temperatures in the range 40-60°C. Actual penetrant concentrations were determined from the sorption balance. The diffusion coefficients from the two techniques agree very well with each other. In addition, the diffusivity data from both techniques could be correlated successfully as a function of temperature and concentration with the Vrentas and Duda free-volume model. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1261-1267, 1997
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    The effects of glass beads and silane treatments on the curing behavior of a brominated epoxy resin: DSC analyses (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2063-2071 
    Details
    ISSN: 0887-6266
    Keywords: brominated epoxy resin ; dicyandiamide ; curing kinetics ; glass bead ; silanes ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The curing characteristics of a brominated epoxy resin/dicyandiamide (DICY) system filled with silane-treated glass beads are studied using isothermal differential scanning calorimetry (DSC). Three different silane coupling agents, N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane, N-[2-(vinylbenzylamino)-ethyl]-3-aminopropyl-trimethoxysilane, and 3-glycidoxypropyl-trimethoxysilane, are applied. It is found that the reaction heats of the epoxy system are little affected by the curing temperature and the untreated glass fillers, but changed with the addition of silane-coated glass beads. The effect of glass beads on the curing reaction is more significant at the low curing temperature and conversion. The silane treatment results in changes in Tg, activation energy, reaction heat, reaction rate, and reaction order. Three silanes respond differently because of their differences in the activated reaction with the matrix system. Regardless of the various curing mechanisms involved, a simple kinetic expression can describe the curing extent at 170 and 180°C with a good accuracy for all systems studied. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2063-2071, 1997
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Multicomponent diffusion of methyl ethyl ketone and toluene in polyisobutylene from vapor sorption FTIR-ATR spectroscopy (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 337-344 
    Details
    ISSN: 0887-6266
    Keywords: infrared spectroscopy ; multicomponent ; diffusion ; polymer ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this study, diffusion coefficients of toluene/methyl ethyl ketone (MEK) mixtures in polyisobutylene were measured at 50°C using vapor sorption FTIR-ATR (Fourier Transform Infrared Attenuated Total Reflectance) spectroscopy. For three mixture compositions, the diffusion coefficients were determined using a diffusion framework for ternary systems. The “crossterm” diffusion coefficient for MEK was found to be very small under the experimental conditions studied here, while that for toluene was found to increase with increasing MEK concentration. On the basis of this finding, a binary diffusion model was used to determine diffusion coefficients for MEK over a wide range of mixture compositions and the results compared well with those determined from pure MEK transport data. Relative transport rates during integral sorption experiments with mixtures were used to explain the results. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 337-344, 1998
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    The elongation and time dependence of the crystallinity of low-density polyethylene (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1945-1957 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been presumed in studies of the orientation of low-density polyethylene and its time dependence that the degree of crystallinity remained constant with elongation and did not vary with time following elongation. This paper represents a test of this hypothesis by several methods. The change in crystallinity accompanying stretching has been followed by a modification of an x-ray method for uniaxial orientation proposed by Ruland in which diffraction peaks are resolved into crystalline and amorphous components and their respective areas are determined by two-dimensional integration over both the Bragg angle and the azimuthal angle of diffraction. The weight-fraction crystallinity is then determined from the ratio of the weighted crystalline area to the total area. There appears to be no significant variation in crystallinity up to 50% sample elongation for both slowly and rapidly stretched samples at room temperature. The dynamic crystallinity change accompanying small amplitude vibration has also been determined by the dynamic x-ray diffraction technique and found to be negligible over a wide range of frequency. The degree of crystallinity has also been evaluated from the absolute infrared absorbance of crystallinity-sensitive bands and has also been found to be independent of elongation at room temperature up to 80% elongation. Changes have also been observed by this method during relaxation at constant length following rapid extension and have also been found to be negligible. These results also indicate negligible changes in rotational isomer population. Consequently, we conclude that changes observed during relaxation and vibration arise from orientational changes rather than changes in the degree of crystallinity.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.180131009
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  • 5
    Electronic Resource
    Electronic Resource
    Viscoelastic properties of entangled polymers. II. The interchain-intrachain entanglement model (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 15 (1977), S. 1869-1883 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Our earlier model of entangled chain dynamics represented the elastic effects at entanglement points as a coupling with the surrounding medium, which was propagated weakly to every other entanglement site on the parent chain. In this way, a great variety of linear viscoelastic phenomena could be successfully predicted, with the only significant deficiency being a quantitative failure in curve fitting the local minimum in dynamic loss modulus G″(ω). Here we introduce the “intrachain entanglement,” or the “internal entanglement,” in which the parent chain entangles directly with itself. Elastic forces between pairs of internal entanglements are assumed to be stronger than those with the medium (“external entanglement”). Predictions of the new model are compared with rheological data on monodisperse polystyrene. Good agreement is obtained between theory and experiment, including G″(ω).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.180151101
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of internal field on the birefringence of polyethylene crystals and on the anisotropy of polymer chains. I. Birefringence effects (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1447-1459 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Values of the anisotropy of polarizability of methylene groups deduced from the refractive indexes of n-paraffin crystals differ appreciably from those obtained from gas- or liquid-phase measurements. The differences is attributed to the erroneous application of the Lorenz - Lorentz internal field to the anisotropic n-paraffin crystal. A more detailed calculation of the internal field is carried out by detailed summation of the dipolar field over an idealized n-paraffin crystal in which the molecular chains are replaced by anisotropic rods. With reasonable values of parameters and assumed crystal shape, the discrepancy in polarizability anisotropy is resolved.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.180130714
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Small-angle light scattering by random assemblies of incomplete spherulites. Systems with partial degree of volume filling (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 49-58 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theory is presented to account for the effect of the impingement of growing spherulites on their Hv small-angle light scattering patterns. The theory is developed on the basis of results of computer-simulated two-dimensional spherulite growth and calculated scattered intensities. The impingement produces a lowering of the intensity of the scattering maximum and the diminishing of the overall sharpness of the scattering peak. The extent of these effects increases with area fraction of spherulites. A procedure is suggested for determining correction factors that may be applied to intensity data obtained during the course of spherulite crystallization. An interpretation is made of the type of average spherulite size determined from the scattering angle of maximum intensity.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.180190105
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  • 8
    Electronic Resource
    Electronic Resource
    A new technique for measuring poisson's ratioThis paper presents the results of one phase of research carried out at the Jet Propulsion Laboratory, California Institute of Technolgoy, under Contract No. NAS7-100 sponsored by the national Aeronautics and Space Administration. (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 777-781 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.180200419
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