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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 5 (1954), S. 359-359 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 15 (1964), S. 700-701 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 129-150 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Study of the diffusion in polymers of molecules comparable in size and structure to the segments of the chain molecules is suggested as a means of securing information on structure and molecular friction forces in polymers. A convenient method for measuring the diffusivity in polymers of such compounds tagged with C-14 was devised and used to study the diffusivity of octadecane, octadecanol, stearic acid, and octadecyl stearate for a range of temperatures in polymers including natural rubber, GR-S, polybutadiene, polyisoprene, and polyisobutylene. Diffusivities were independent of concentration for the range used. The diffusivities of straight chain hydrocarbons in natural rubber appear to vary inversely as the molecular weight of the diffusing compound. Evidence was found for association effects in the diffusion of stearic acid in natural rubber. Activation energies for diffusion of the compounds were quite similar in any one polymer and of the same order as reported for low molecular weight hydrocarbons and for viscous flow. Larger differences in activation energies were observed for diffusion in the different polymers. Correlations were observed for the diffusivities of octadecane in a series of polymers with their densities and thermal expansivities, especially the latter. Some study was given to the effect on the diffusivity of octadecane of such parameters as polymer unsaturation, solution viscosity, molecular weight, and crosslink density. The diffusivity of octadecane in natural rubber had a pronounced maximum as a function of crosslink density, coinciding with the maximum in tensile strength. Possible implications of this are discussed. The diffusivities of octadecane in a series of elastomers were studied in relation to the internal frictional losses observed for 60 cps vibrations over a range of temperatures. It was concluded that frictional forces deduced from the diffusivity measurements have some correspondence to high frequency viscoelastic phenomena which involve small units of structure comparable in size to the segments of the polymer molecules.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 14 (1976), S. 1083-1087 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cleavage of poly(vinyl alcohol) in dimethyl sulfoxide at 42°C has been measured viscometrically in the presence of tert-butyl hydroperoxide and metal complexes. Phthalocyanine complexes of copper(II), iron(III), cobalt(II), and vanadium as VO(II) as well as hemin, hematin, chlorophyllin, and cytochrome c were used. The rates of decomposition of tert-butyl hydroperoxide in the presence of these metal complexes were measured idometrically. These data are compared to results obtained with other metal complexes in similar reactions.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 91-103 
    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 isothermal decomposition of a phenolic resin in a phenolic-carbon cloth composite was measured in air at 0.1 to 0.2 torr over the temperature range 104-718°C. Two decomposition rate relationships are presented that can be used to predict decomposition. One assumes two second-order consecutive rate-controlling reactions, and the other assumes a diffusion-limited second-order reaction. Two rate constants govern each relationship, one being operative during the initial decomposition stages, and the other during the final stages. Evidence is presented to support the applicability of both relationships to predict decomposition over the entire temperature range studied. Arrhenius plots of the rate constants consist of several segments linearly connected. Activation energies and frequency factors computed from these segments cover a broad range of values. The activation energies are used to correlate the temperature ranges with the predominant products formed in these ranges.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    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 of water by nylon 66 and Kevlar 29 fabrics was studied over a range of 20-98% relative humidities at 27°C. Equilibrium and rate relationships were developed from the data in this study and from nylon 66 and nylon 6 data of other studies involving fiber and film. The ratio of sorbed moisture to amide concentration is, on average and at high relative humidities, one water molecule per amide unit. The nylon equilibrium data show that there exist threshold relative humidities above and below which sorption properties differ. One threshold is correlated with the glass transition. Another is identified in the glassy state of nylon 6 in which moisture is tightly bound. The equilibrium constant values are highest and the moisture is most tightly bound at very low humidities, and the values are lowest in the plastic region at high humidities. NMR, DSC, and mechanical property data from others are correlated with the sorption discontinuities observed in this study. Rate data indicate that sorption is a diffusion-controlled process.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 7
    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 tensile strength degradation of nylon 66 and Kevlar 29 yarns was studied at elevated temperatures and over a broad range of relative humidities. The degradation rates for nylon are initially slow but increase rapidly, suggesting the depletion of an inhibitor. Kevlar showed no evidence for similar inhibitor action. The effect of relative humidity on degradation can be very large, especially at values in the 90-100% range and at elevated temperatures. Degradation is governed by thermal-oxidative and moisture-induced mechanisms. At the very high humidities and elevated temperatures, the moisture-induced degradation predominates. Rate relationships were developed in which contributions from each mechanism were considered. Calculated degradation from these relationships agrees well with observed degradation over a broad range of temperatures and humidities.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 407-415 
    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: Organosolv lignin was fractionated on a Sephadex G 75 column with 0.1M aqueous NaOH resulting in 14 fractions. These fractions were acetylated and a high-molecular-weight fraction (F3) was investigated by means of combined static and dynamic light scattering (LS) in solvents acetone, tetrahydrofuran (THF), and trifluoroethanol (TFE). The measurements were found to be reproducible, and recycling of lignin by freeze drying caused slight but unessential changes in solution properties. Depending on the solvent used, weight average molecular weights Mw between two and ten million were found. By contrast, Mn of the fractions, measured by vapor pressure osmometry (VPO), was in the range of a few thousands only. Analysis of the angular dependence in static LS by means of a Casassa-Holtzer plot and the fractal dimensions showed the presence of chain stiffness, most distinct in TFE. Also, the dynamic light scattering results in TFE are typical for semiflexible chains, while in THF, and to some extent in acetone, the dynamic measurements including viscosity suggest the presence of spherical structures. These findings are being explained by large lignin clusters that consist of stiff subunits.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 3 (1992), S. 323-329 
    ISSN: 1042-7147
    Keywords: Polyanhydrides ; Pulmonary neoplasms ; Mice ; Chemotherapy ; Cisplatin ; BCNU ; 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
    Notes: Investigations were undertaken to determine whether anti-cancer drugs introduced locally into the lung using bioerodible polyanhydride microspheres as carriers would demonstrate both efficacy and reduced toxicity.BCNU (carmustine) and CDDP (cisplatin), loaded in polyanhydride microspheres, were administered to mice bearing either of two tumors selected for their affinity for the lung: the B16F10 melanoma and the recently established GL26F4 glioma. Following intravenous inoculation of these tumor cells, the number of metastatic foci formed in the lung follows a predictable time course and can readily be determined. Comparisons were made between the efficacy of microspheres introduced into the lung by intratracheal intubation (IT) and of those administered by intraperitoneal injection (IP). Administration of microspheres loaded either with BCNU or cisplatin reduced the detectable metastatic foci by 25-90% depending on the tumor load, both when administered IP and IT.Toxicity was assessed by flow cytometric analysis of bone marrow cellularity as well as by determination of mortality rates. Intratracheal administration of either cisplatin or BCNU reduced the deleterious systemic effects observed when the drug was administered by IP injection. This was seen at high drug levels, where significant mortality occurred only in animals given drug injections IP; and at lower levels where IP injection led to a reduction of bone marrow blast cells, while IT administration caused no detectable effect on marrow cellularity.Since local delivery of BCNU or cisplatin through bioerodible polyanhydride microspheres induces significantly less systemic damage while demonstrating efficacy equal to or exceeding that of IP injection, this mode of drug delivery warrants further and more detailed exploration. Moreover, the method may be applicable to the treatment of other chronic pulmonary pathologies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1042-7147
    Keywords: Silk ; Mechanical ; Spider ; Silkworm ; Thermal ; 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
    Notes: Dragline silk from the spider, Nephila clavipes, was characterized by thermal analysis (TGA, DSC, DMA), computational modeling, scanning electron microscopy and by quasi-static as well as high rates of strain. Thermal stability to about 230°C was observed by TGA, two transitions by DMA, -75°C, representative of localized motion in the amorphous domain, and a main chain motion associated with partial melt at 210°C. Tensile tests indicated average initial modulus, ultimate tensile strength and ultimate tensile strain of 22 GPa, 1.1 GPa and 9%, respectively. The corresponding properties of the best fibers tested were 60 GPa, 2.9 GPa and 11%, respectively. High strain rates (〉50,000%/sec) indicated similar mechanical properties to the average values indicated above. Microscopy showed compressive and tensile strains to failure of 34%. Computational modeling yielded a crystal modulus of 200 GPa.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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