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  • Polymer and Materials Science  (74)
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  • 1
    Electronic Resource
    Electronic Resource
    Evolution of H2O and CO2 during the copper-catalyzed oxidation of isotactic polypropylene (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 389-403 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechanism of H2O and CO2 evolution during uncatalyzed and copper(oxide)-catalyzed (Cu, CuO, CuO0.67) oxidation of isotactic polypropylene have been investigated in detail for various catalysts over a range of temperatures (90-150°C). These volatiles were determined chromatographically; H2O and CO2 represent the main volatiles of the oxidation, comprising about 80 mol % of all volatiles. Uncatalyzed oxidation evolves ca. 1 mol of H2O and 1 mol of CO2 for each unit mole of polymer oxidized, while catalyzed oxidation produces 2 mol of H2O and ca. 1.2 mol of CO2 for each unit mole of polymer. These results indicate that secondary as well as tertiary H atoms on the polymer chains are involved in hydroperoxide formation and decay. The oxidation mechanism has been formulated and evaluated on this basis. It consists essentially of two parallel oxidation reactions involving tertiary and secondary groups (H atoms and hydroperoxides), respectively. The mechanism can be represented by first- and pseudo-first-order reactions in series: (1) oxygen absorption showing induction periods; (2) hydroperoxide formation and decay (plateaus are reached); (3) H2O evolution from the decay of hydroperoxides; and (4) subsequent CO2 production involving chain scission. Arrhenius parameters for all oxidation reactions (uncatalyzed and catalyzed) are also presented. It appears that CuO0.67 is the most efficient catalyst of those investigated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240301
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  • 2
    Electronic Resource
    Electronic Resource
    Ozone gas analysis by polymer chain scission (1969)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 7 (1969), S. 101-109 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde eine neue Methode entwickelt zur Bestimmung kleiner Mengen Ozon in Luft durch Kettenspaltung von Polymerfilmen.Die vorgeschlagene Methode hat für hochmolekulares Polystyrol (M̄v = 1,8 × 106) eine Empfindlichkeitsgrenze von 2 ppm Ozon in Luft. Dagegen hat Butylkautschuk (M̄v = 5,62 × 105, 1,75 Gew.-% Isoprenbausteine) eine niedrigere Empfindlichkeitsgrenze von 0,02 ppm ± 20% bei 35°C und 24 Stdn. Reaktionszeit. Die Grenze kann durch höhere Temperaturen wesentlich herabgesetzt werden. Eine noch höhere Empfindlichkeit läßt sich prinzipiell erreichen mit höhermolekularem Butylkautschuk mit größerem Isoprengehalt.
    Notes: A novel method has been elaborated for the determination of small amounts of ozone in air by chain scissioning of polymer films due to the high reactivity of ozone.The proposed method has a sensitivity limit for high molecular weight of polystyrene (M̄v = 1.8 × 106) of 2 p.p.m. of ozone in air. However, a butyl rubber (M̄v = 5.62 × 105, 1.75% by weight of isoprene) has a lower sensitivity limit of 0.02 p.p.m. ± 20% at 35°C and 24 hours reaction time. The latter can be decreased considerably if higher temperatures are used. Still lower sensitivity limits could be in principle attained with butyl rubber of longer chain length and higher isoprene content.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1969.050070109
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  • 3
    Electronic Resource
    Electronic Resource
    Photodegradation of polyacrylonitrile in solutionPresented at the 9th Canadian High Polymer Forum, Toronto, October 26-28, 1959. (1960)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 3 (1960), S. 206-212 
    Details
    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 ultraviolet photodegradation of polyacrylonitrile was studied at 25°C. with irradiation with light of wavelength 2537 A. Polymer dissolved in a 80%/20% mixture by weight of ethylene carbonate and propylene carbonate was irradiated. Preliminary experiments indicated that in the presence of oxygen predominantly chain scission takes place, whereas in its absence chain scission and recombination of radicals seem to occur. There is also a dark reaction which proceeds for appreciable periods of time after exposure. Quantitative studies were performed in vacuo at 25°C. in the ethylene carbonate-propylene carbonate mixture as solvent. Degradation was followed by determining intrinsic viscosities as a function of time at various light intensities. The quantum yield was found to be 7.7 × 10-4 chain scissions for each quantum absorbed under the given experimental conditions. Infrared spectra of original and irradiated polymer samples indicate that there is no change in the overall structure of the polymer chains. The experimental results can be satisfactorily represented by the theory of random breaking of bonds assuming that the rate of breaking bonds is proportional to the number of bonds present at any time t and to the light intensity. The experimental rate constants derived on the basis of the random theory were actually found to be linearly dependent on the light intensity.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1960.070030810
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  • 4
    Electronic Resource
    Electronic Resource
    Photodegradation in solution (1960)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 4 (1960), S. 253-253 
    Details
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1960.070041126
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  • 5
    Electronic Resource
    Electronic Resource
    Diffusion of Cu2+ catalysts from Cu-metal polymer or Cu-oxide/polymer interfaces into isotactic polypropylene (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 503-510 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diffusion coefficients of Cu2+ in the form of its carboxylate have been measured in isotactic polypropylene as a function of temperature (90-128°C) and extent of preoxidation. Diffusion take place from the metal catalyst/polymer interface into the bulk polymer. The diffusion is dependent on the extent of preoxidation and temperature but not on the type of catalyst (Cu, CuO, CuO0.67). Analysis of polymer sections for Cu2+ ions was carried out with a selective Cu2+ electrode. Diffusion in isotactic polypropylene is about 1000 times faster than in lowdensity polyethylene. The carboxylate anion appears to have about 7 C-atoms for diffusion in isotactic polypropylene compared with 29 C-atoms for low-density polyethylene.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1986.090240303
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  • 6
    Electronic Resource
    Electronic Resource
    Reaction of SO2 with polymer (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2504-2505 
    Details
    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
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131123
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  • 7
    Electronic Resource
    Electronic Resource
    Diffusion of poly(vinylpyrrolidone) through cellulose ester membranes (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 527-533 
    Details
    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: Diffusion coefficients of poly(vinylpyrrolidone) in aqueous solutions were ascertained by the diaphragm method as a function of molecular weight and temperature using mixed cellulose ester (Millipore) membranes. The results agree satisfactorily with diffusion coefficients obtained by other methods. Separation of polymer according to molecular size takes place on diffusion as a function of membrane pore diameter. Also, interaction between the polymer and membrane has been observed resulting in a distribution coefficient between solution and membrane larger than 1. The energy and entropy of activation, repectively, increase with polymer chain length, and their magnitudes are in agreement with the view that segment mobility is operative for the diffusion process.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160221
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  • 8
    Electronic Resource
    Electronic Resource
    Reaction of SO2 and NO2 with polymers (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 107-116 
    Details
    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: A number of polymers have been exposed to SO2 and NO2 gas under various conditions. Chain scission, crosslinking reactions, and changes in infrared spectra have been noted. All polymers suffer some deterioration, which may be considerable with exposure over long periods of time. Elastomers form a separate group, being appreciably more susceptible to these gases than saturated polymers; however, they are still more sensitive to ozone.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130112
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  • 9
    Electronic Resource
    Electronic Resource
    Tensile strength of polyurethane exposed to nitrogen dioxide (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1773-1778 
    Details
    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: Polyurethane prepared from tetramethylene glycol and diisocyanate was exposed in the form of films to small pressures of NO2 and to NO2 plus air. Tensile strength was measured as a function of exposure time and temperature with an apparatus especially constructed for the purpose of measuring mechanical properties in different environmental “atmospheres.”
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180615
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  • 10
    Electronic Resource
    Electronic Resource
    New static and dynamic stiffness testers (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 2963-2972 
    Details
    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: Instruments have been developed for the testing of stiffness of polymers in various gaseous environmental “atmospheres” over a large range of temperatures. They are based on the cantilever principle, where a small strip of a specimen is deflected statically or periodically. Changes in stiffness are measured as function of the bending force or power input, respectively. The dynamic instrument responds very sensitively to the onset of cracking in specimens due to ozone exposure. The static instrument is well suited for measuring the onset of rapidly increasing stiffness as temperatures are lowered.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070181009
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