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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 3731-3738 
    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 sorption kinetics of p-nitrophenol (PNP) onto undrawn nylon yarn from an organic, nonswelling solvent in a dye bath in which the concentration of PNP was being depleted were found to obey Hill's solution of the diffusion equation, suggesting the presence of a monolayer of absorbed PNP at the surface of the fiber. Diffusion coefficients were obtained using a nonlinear least-squares curve-fitting computer program. For undrawn nylon samples, oxidized for various lengths of time prior to dyeing, the diffusion coefficient increased as a function of oxidation time, rising particularly rapidly once the fibers developed microscopically visible surface cracks. The dependence of diffusion coefficient on oxidation time implies that oxidative degradation of the material is accompanied by formation of submicroscopic incipient cracks, permeable by PNP, of which at least some eventually develop into visible cracks after sufficient oxidation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 15 (1977), S. 263-277 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acoustic absorption and adiabatic compressibility measurements are reported on solutions of polystyrene (Mn = 89,000) in toluene and cyclohexane. The data in toluene cover a temperature range from 293 to 343°K and a concentration range of 10-400 Kg m-3 (1-40 wt%). The dependence of acoustic absorption on concentration was found to be linear up to 100 kg m-3, which corresponds to the concentration at which polymer-polymer interactions cause significant changes in the specific viscosity-concentration relationship. Up to 200 kg m-3 the data could be fitted to computations based on an artificial separation of the dispersion into contributions from viscoelastic and segmental processes, using parameters obtained from a study of narrow molecular weight distribution samples at 25 kg m-3. However, neither approach was capable of describing dispersions in the 300, 400 kg m-3 solutions. The modification of the relaxation spectrum observed at the highest concentrations is ascribed to volume and entropy changes associated with alterations of the local environment around a segment of the polymer chain. These changes have their origin in interchain penetration and polymer-polymer contacts, and indicate that ‘entanglement’ is primarily entropic in effect.The adiabatic compressibility exhibited similar deviations from a simple concentration dependence, and allowed estimation of an incompressible volume increment associated with polymer-polymer interactions in the high-concentration entangled matrix. However, the adiabatic compressibilities of solutions of polystyrene, 10-15 kg m-3, in cyclohexane showed no deviations from simple behavior in the region of the theta temperature. Measurements of the adiabatic compressibility of polystyrene in mixtures of cyclohexane-toluene have been used to obtain the relative magnitude of solvent and polymer contributions to the excess compressibility.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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