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  • Physics  (704)
  • Atomic, Molecular and Optical Physics  (214)
  • Wiley-Blackwell  (918)
  • National Academy of Sciences
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 7 (1969), S. 889-896 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is demonstrated that in a filled polymer the thermal stresses resulting from the difference in the thermal expansion coefficients of the filler and the polymer have significant effect on the apparent coefficient of thermal expansion of the composite. A model is constructed to aid the thermal stress analysis, and the results are found to agree well with the experimental data obtained from other sources. An expression for the apparent densities of filled polymers is also obtained but the agreement between the present prediction with an existing test result is found to be only qualitative.
    Additional Material: 6 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 7 (1969), S. 879-887 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Fickian diffusion coefficient of methylene chloride in a glassy epoxy polymer is calculated with the use of Crank's model of discontinuous change of D with concentration C. The diffusion constant is obtained as 1.93 × 10-6 cm2/sec. The swollen layer behind the advancing solvent front is essentially in the rubbery state of the same polymer. The case II swelling by benzene is discussed in terms of a convective transport arising from the partial stress (internal) tensor of the penetrant. The superposition of Fickian and case II diffusion found with mixtures of methylene chloride and benzene is also discussed briefly.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 2597-2605 
    ISSN: 0887-6266
    Keywords: positron annihilation ; open space ; relaxation ; subsurface ; polyethylene ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Open spaces in the subsurface region (〈10 μm) of very low density polyethylene were probed by a monoenergetic positron beam. From measurements of Doppler broadening spectra measurements of the annihilation radiation and the lifetime spectra of positrons as a function of incident positron energy, the size of the open spaces in the region of 0-3 μm was found to be larger than that in the deeper region. This was attributed to the cooperative motion of large segments of molecules which is activated near the surface. After the freezing in of such motions (below 230 K), although the lineshape parameter S in the bulk was almost constant, S in the region of 0-3 μm decreased with decreasing temperature. This discrepancy was associated with the presence of the open spaces with an excess content and the resultant contraction of amorphous structure near the surface. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2597-2605, 1998
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 7 (1969), S. 2019-2028 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The diffusion studies of several solvents in epoxy polymer reported by Kewi and Zupko in Part I of this series are explained with the solution obtained from the generalized diffusion equation which includes the internal stress contribution. The rate of permeation of a penetrant through a polymer film and the time lag needed to reach steady state are also given for the generalized diffusion equation.
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 853-864 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyenes formed in the thermal degradation of PVC are readily oxidized in the liquid phase in the presence of a radical initiator. In pure oxygen at a constant rate of initiation, different length polyenes are consumed by a first-order reaction: the rate of consumption is proportional to the polyene length and to the square root of initiator concentration. Applying the relationships given by the theory of chain reactions, we determined the ratio of the rate constant of chain propagation calculated for one double bond k2 to the square root of the chain-termination rate constant k4. The value obtained, which is relatively high in comparison to other unsaturated hydrocarbons, reflects very well the high reactivity of polyenes of the degraded PVC sample towards oxidation. Intramolecular chain propagation steps are also likely to play a role in the oxidation of polyenes.
    Additional Material: 10 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 1547-1550 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The free polymerization of 2-methyl-1-vinylpyrrol (I), 2,3-dimethyl-1-vinylpyrrol (II), 1-vinyl-4,5,6,7-tetrahydroindol (III), 1-vinyl-2-phenylpyrrol (IV), and 1-vinyl-2-phenyl-5-trifluoroacetyl pyrrol (V) in the presence of azobisisobutyronitrile as an initiator at 60-80°C has been studied. The polymer yield (up to 90%) and molecular weight in the range 2000-13,000 are strongly dependent on the monomer structure and the polymerization conditions. The reactivity of N-vinylpyrrols studied falls in the order: I 〉 III 〉 II 〉 V 〉 IV implying an important role of the initial radical stabilization with the participation of the ring substituents as well as the steric hindrances in the propagation stage.
    Additional Material: 2 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 1287-1298 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five polyimide films prepared from 3,3′,4,4′-benzophenone tetracarboxylic acid'dianhydride (BTDA) and diamines, 4,4′-oxydianiline (ODA), 3,3′-diaminobenzophenone (DABP), or 3,3′-diaminodiphenylcarbinol (DADPC) and doped with Li2PdCl4 (LTP) or Pd[(CH3)2S]2Cl2 (PDS) were selected for a detailed x-ray photoelectron spectroscopic (XPS) study to determine the oxidation state of palladium and the relative distribution of this and other elements in these films, especially as they relate to electrical resistivity. XPS shows that Pd in the films is present as a mixture of zero and +2 valence states. Films that contain lithium as part of the dopant all show that metal is present as Li+ and Li2O, a fact that may have a bearing on film electrical properties. An Auger electron spectroscopic (AES) or XPS profiling was performed on two of the electrically conductive films. A film doped with PDS reveals a majority of palladium at the surface as Pd(0) and much smaller amounts in film bulk as a mixture of Pd(0) and Pd(II). Film behavior is similar to a metal-vapor deposited film. An LTP doped film, by contrast, exhibits a homogeneous composition with a mixture of Pd(0) and Pd(II). These studies support others that use chemical etching on the film surfaces. Scanning electron microscopy (SEM) has been used to provide surface evaluations.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 2393-2402 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From the analysis of the permeation of 35S labeled ethanesulfonic acid, through nylon-6 films sorption isotherms were obtained. The films are characterized by their largely different content of carboxyl and amino end groups. It was found that the shape of the isotherm depends on the molar ratio of the two end groups: an S-shape curve for the film containing the carboxyl end group larger than the amino end group and a Langmuir-type curve for the film containing comparable numbers of end groups. These results were explained by the McGregor-Harris theory in which the acid dissociation constants of the two end groups in nylon were estimated experimentally.
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 7 (1969), S. 3129-3141 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: To elucidate the propagation mechanism in the cationic polymerization of vinyl ethers and β-substituted vinyl ethers, the electron distribution in these monomers was computed by the extended Hückel method. Propylene and styrene derivatives were also studied in comparison with the vinyl ether derivatives. Attempts were made to explain the experimental results by various calculated reactivity indices. With the unsaturated hydrocarbons, the reactivity indices on the β-carbon parallel with the relative reactivity in the cationic polymerization or oligomerization. This agreement suggests that the transition state for the rate-determining step of the propagation reaction is represented by a model in which the carbonium ion interacts with the β-carbon of a monomer. On the other hand, the effect of β-alkyl or alkoxyl groups on the reactivity of vinyl ethers could not be explained by the model in which the carbonium ion interacts with an olefinic carbon or an ether oxygen, or both with two atoms. The following model was proposed on the basis of the electronic stabilization energy due to the de- localization from the occupied orbital of a monomer to the vacant orbital of a carbonium ion. This model can explain reasonably the relative reactivity of vinyl ethers and β-substituted vinyl ethers observed in the cationic copolymerization catalyzed by BF3·O(C2H5)2.
    Additional Material: 6 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 259-273 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By means of bromine labeling and ESR, the grafting reactions of styrene onto preirradiated polyethylene have been investigated. Not all the radicals produced by irradiations participate in grafting reactions all together, but they are rendered active bit by bit by the swelling of crystalline parts of polyethylene. The growing rates for polystyryl graft chains at 20°C decrease from 4 monomer units/active site/sec to one-fourth the initial value after 100 min. On the contrary, the average lifetimes increase from 〈103 sec to 〉2.6 × 103 sec. The number-average molecular weight of graft chains also increases with reaction times and rises to 3.5 × 105 after 90 min at 20°C.
    Additional Material: 15 Ill.
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