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  • Physics  (492)
  • Wiley-Blackwell  (492)
  • 1975-1979  (492)
  • 1976  (492)
  • 1
    Electronic Resource
    Electronic Resource
    Dynamics of macromolecular chains. III. Time-dependent fluorescence polarization studies of local motions of polystyrene in solution (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 11-27 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fluorescence anisotropy decay experiments are described for polystyrene in various ethylacetate-tripropionin mixtures. Decay curve trends agree with the proposed theoretical autocorrelation function. Study of the effects of viscosity shows that the mean relaxation time varies according to a nonlinear law for low viscosities and that the relaxation time θ, reflecting the effects of the possible departures from the motions permitted by an ideal tetrahedral lattice, obeys a law of the type: θ = α + bη. Furthermore, the effects of the direction of the fluorophore transition moment are examined.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140102
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  • 2
    Electronic Resource
    Electronic Resource
    Quasielastic scattering by dilute polymer solutionsA summary of this work was presented at the IUPAP International Conference on Statistical Physics, August 25-29, 1975. (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1-10 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The scattering law S(k,w) for dilute polymer solutions is obtained from Kirkwood's diffusion equation via the projection operator technique. The width Ω(k) of S(k,w) is obtained for all k without replacing the Oseen tensor by its average (as is done in the Rouse-Zimm model) using the “spring-bead” model ignoring memory effects. For small (ka\documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt N $ \end{document} ≪ 1) and large (ka ≫ 1) values of k we find Ω = 0.195 k2/β α η0 \documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt N $ \end{document} and Ω = k2/βξ, respectively, indicating that the width is governed mainly by the viscosity η0 for small k values and by the friction coefficient ξ for large k values. For intermediate k values which are of importance in neutron scattering we find that in the Rouse limit Ω = k4a2/12βξ. When the hydrodynamic effects are included, Ω(k) becomes 0.055 k3/βη0. Using the Rouse-Zimm model, it is seen that the effect of pre-averaging the Oseen tensor is to underestimate the half-width Ω(k). The implications of the theoretical predictions for scattering experiments are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140101
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  • 3
    Electronic Resource
    Electronic Resource
    Ion recombination luminescence in polymer glasses induced by electron irradiation. I. High-vinyl polybutadiene (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 437-449 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The luminescence of 1,2-polybutadiene was measured during and following irradiation with 1.4-MeV electrons at 90 °K. Measured under isothermal conditions, the light intensity at first increases sharply on start-up of irradiation, and then reaches a plateau after several seconds. The equilibrium value was found to be linearly dependent on the dose rate employed. The postirradiation luminescence decay measured at 90°K follows second-order kinetics.The light emitted by the irradiated sample during warm-up to room temperature is characterized by the appearance of four intensity maxima at 118, 168, 223, and 261 °K. The first three peaks are attributable to the onset of local motion, whereas the peak at 223 °K is caused by the long-range motion occurring at the glass-to-rubber transition. A preirradiation of the polymer in vacuo causes an increase in these four peaks as well as the formation of a new maximum at 143 °K.Intermittent exposure of the irradiated sample to light of wavelengths λ 〉 450 nm causes the isothermal luminescence decay to be interrupted by a burst of light emitted by the sample during and shortly following the light exposure. This treatment also results in considerably reduced intensity maxima during warm-up to room temperature. An interpretation of the findings reported is given on the basis of reactions involving primary and secondary transient species produced during irradiation and on the molecular parameters of the polybutadiene.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140306
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  • 4
    Electronic Resource
    Electronic Resource
    Piezoelectric properties of oriented films of poly(γ-methyl D-glutamate) (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 401-414 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic piezoelectric stress constant e*25 of drawn films of poly(γ-methyl D-glutamate) (PMDG) cast from solutions in α-helix-promoting solvents 1,2-dichloroethane (DCE) and chloroform and from the nonhelicogenic solvent dichloroacetic acid (DCA) was measured from -180°C to 200°C at 110 Hz. The drawn and annealed films cast from chloroform show a small peak for the real part of piezoelectric stress constant -e′25 in the temperature range of the mechanical α2-crystalline relaxation, which is caused by the distortion motion of the backbone chain of the α-helix. On the other hand, drawn films cast from DCE show the peak of the real part of the piezoelectric stress constant, whose magnitude decreases in the range of the mechanical α1-crystalline relaxation or the β-relaxation processes, which were previously ascribed, respectively, to mutual slipping of α-helices and to the micro-Brownian motion of disordered regions. Also, -e′25 becomes virtually zero near 180°C where the α2-relaxation is located. These results suggest that the polarization change induced by applied strain is caused by distortion of the backbone chains in the α-helix. Near 0°C, the temperature range of the side-chain mechanical relaxation, -e′25 exhibits a marked peak both for films cast from chloroform and from DCE. The maximum value of -e′25 and the orientation function of the α-helix axis are linearly related and extrapolation of -e′25,max to unit orientation function gives 1.3 × 104 cgs esu which corresponds to 2.4 Debye per residue. This value corresponds reasonably to the value of 3.71 Debye for the permanent dipole moment of NHCO bond if the correction for crystallinity is made. This result also indicates the piezoelectric properties of PMDG arise from distortion of the backbone chain of the α-helix induced by applied strain.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140303
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  • 5
    Electronic Resource
    Electronic Resource
    An anomalous transition to a lower activation energy for dc electrical conduction above the glass-transition temperature (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 955-957 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; 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.1976.180140516
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative information from x-ray diffraction of nylon-6 yarns. II. Physical aspects of some quantitative parameters (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 941-954 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A mathematical model developed in an earlier paper describes the experimental x-ray profiles of equatorial nylon-6 reflections in terms of Pearson VII functions. The present paper deals with the physical aspects and interpretations of the interrelations of the parameters obtained and the relation between these parameters and the results of other types of measurements. It was found that the growth of the crystallites perpendicular to the chain axis is not isotropic, the strongest growth being in the direction of the hydrogen bonds. Growth and perfection of the crystallites are found to be highly correlated. Large crystals are related to short distances between the planes containing the hydrogen bonds and so to densely packed, i.e., perfect unit cells. This correlation forms the basis for the observed similarity between our quantification technique and the method of the crystal perfection index introduced by Statton. Curve resolution, however, makes the method better applicable for poorly crystallized samples. Comparison of the results with those of small-angle x-ray scattering gave a high degree of consistency with respect to the determined crystal size. In the literature mention is made of a relation between the dimensions and the melting point of the crystals; this relation is confirmed by comparing the appropriate x-ray parameters with DTA results of methoxymethylated nylon 6-yarns.Information about the γ-phase can be obtained from equatorial and meridional reflections. The expected relationship between the relevant peak areas was established. This reported evidence shows the physical validity of the parameters obtained using the Pearson VII model for the analytical description of x-ray reflections of nylon-6 yarns.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140515
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  • 7
    Electronic Resource
    Electronic Resource
    Glass transitions of ethyl acrylate-based ionomers (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1201-1209 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The glass-transition temperatures of a series of copolymers of ethyl acrylate and acrylic acid neutralized with various cations were investigated. It was found that a plot of Tg as a function of ion content, for every type of ion investigated here, gives an unusual sigmoidal curve, which can be correlated with the onset of the failure of time-temperature superposition in viscoelastic studies, as will be shown in a future publication. Also, all of the Tg versus concentration curves for the various counterions can be superposed if the plots are made against cq/a, where c is the metal acrylate content, q the cation charge, and a the distance between centers of charge. Furthermore, in one region of water content, a linear relation is obtained between the glass transition and the water content (in weight-%) independent of the ion concentration over wide ranges of ion content. Finally, above an ion concentration of 12 mole-%, the rate of change in Tg per water molecule per ion pair at constant ion content, (∂Tg/∂n)c is linear but with different slopes above and below two water molecules per ion pair.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140705
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  • 8
    Electronic Resource
    Electronic Resource
    Enthalpy relaxation of rigid poly(vinyl chloride) (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1087-1095 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The changes which take place on annealing rigid PVC in the vicinity of the glass transition have been followed by differential scanning calorimetry. The changes appear as an increase in the glass-transition temperature and a decrease in the enthalpy with time of annealing. For annealing at 75°C, the enthalpy after 50-100 hr approaches the value characteristic of the equilibrium liquid state. The results obtained for annealing at 65°C and 75°C are in accord with those expected for the relaxation of an amorphous material, and are at variance with those expected on the basis of crystallization taking place on annealing. The enthalpy relaxation process is characterized by a distribution of activation energies centered about 18.8 kcal mole-1, and seems to reflect a multiplicity of molecular processes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140611
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  • 9
    Electronic Resource
    Electronic Resource
    Newtonian behavior of a styrene-butadiene-styrene block copolymer (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1149-1156 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The melt rheological behavior of an anionically polymerized styrene-butadiene-styrene (SBS) block copolymer sample (S: 7 × 103 and B: 43 × 103) was studied using a Weissenberg rheogoniometer. Highly non-Newtonian behavior, high viscosity and high elasticity, which are characteristics of ABA type block copolymers, were observed at 125°C, 140°C, and 150°C. The data at these temperatures superimposed well onto a master curve giving a constant flow activation energy. However, the data at 175°C indicated a marked change in the flow mechanism between 150°C and 175°C. At 175°C, the sample showed Newtonian behavior, negligible elasticity, and deviation from the master curve. These findings may be considered as an indication that the SBS block copolymer sample undergoes a structural change from a multiphase structure at low temperatures into a homogeneous structure at some temperature between 150°C and 175°C.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140616
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  • 10
    Electronic Resource
    Electronic Resource
    Isotactic poly(pentene-1): Form III (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1161-1167 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new crystalline form of isotactic poly(pentene-1) was obtained from dilute solution in amyl acetate. We have designated it as form III. The morphology and structure of isothermally crystallized samples were investigated by electron microscopy and electron and x-ray diffraction. This crystalline modification can be indexed on an orthorhombic unit cell (cell dimensions: a = 21.20 ± 0.05 Å, b = 11.48 ± 0.05 Å, c = 14.39 ± 0.05 Å (fiber axis) and probable space group P212121).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180140701
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