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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 581-588 
    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: Polymer films were deposited from the plasma polymerization of the mixtures of hydrocarbons, ethane, ethylene, and acetylene, and tetrafluoromethane (CF4) or hexafluoroacetone (HFA). The surface properties, the advancing contact angle of water, and surface energy of the films deposited and the chemical composition at the outermost layer of the films are discussed from the data of the angular XPS measurements. The plasma polymers deposited from the CF4/hydrocarbon and HFA/hydrocarbon mixtures contained fluorine atoms whose content depended on the CF4 or HFA concentration of the mixtures. The hydrophobicity of the films deposited could not be determined by the fluorine content of the films but by the chemical composition of the fluorine moieties at the outermost layer of the films. The CF3 moieties rather than the CF2 and CF moieties contribute largely to the hydrophobicity of the films. The plasma polymer films deposited from the HFA/acetylene (87.5 mol % HFA) showed higher hydrophobicity (the surface energy is 9.7 mJ/m2) than those from the CF4/acetylene mixture (87.5 mol % CF4) (the surface energy is 13 mJ/m2).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 553-558 
    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: Low- and high-density polyethylene (PE) films were grafted with acrylonitrile (AN) by electron beam prior to irradiation. The distribution of graft chains over the cross section of the sample film was analyzed in terms of the distribution of nitrogen atoms contained in the AN by means of an electron probe microanalyzer (EPMA), and graft sites were studied in relation to the effect of grafting temperature on the percent graft and the oxygen permeability of the sample films. It was found that diffusion of AN into the film was the rate-limiting step in the grafting process, thus restricting the grafting to the surface of the film in the initial grafting stages. However, the grafting shifted to the center of film as the graft process proceeded, until a uniform distribution of graft chains was observed across the entire film thickness. High-density polyethylene (HDPE) was found to display a higher percent graft than did low-density polyethylene (LDPE), and percent graft tended to increase with increasing grafting temperature. On the other hand, film oxygen permeability decreased with increasing percent graft, but this decreasing trend decreased with increasing percent graft. These findings suggest that the grafting is initiated by radicals trapped in the amorphous phase near the crystalline regions and at the surface of crystallites and that graft chains grow toward the amorphous regions. As for the radicals contributing to graft polymerization, it appears that AN permeates deeper near the crystalline surface and that graft chains grow from these sites.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 221-225 
    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: Studies were made of the thermal softening and degradation behavior in air of low- and high-density polyethylene (PE) grafted with acrylonitrile (AN) by electron beam prior irradiation in nitrogen. It was found that both LDPE and HDPE were made to exhibit higher softening points by grafting and that this tendency increased with increasing percent graft. The starting temperatures of the thermal degradation and thermogravimetric curves were also found to shift to higher temperatures. On the other hand, in marked contrast to the thermal softening and degradation behavior of grafted PE in air, its behavior in nitrogen showed substantial dependance on oxidative degradation, suggesting that the oxidation of PE was inhibited by polyacrylonitrile (PAN), which forms graft chains. It was considered that the oxidation-inhibiting mechanism of PAN produced in the amorphous regions prevents oxygen from dissolving and diffusing into the amorphous phase, thus inhibiting the oxidative degradation of PE, and that, when heated, PAN undergoes nitrile oligomerization and the nitrile oligomer end radicals act to trap those radicals which participate in PE oxidative degradation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 47-49 
    ISSN: 0935-6304
    Keywords: Ion-exchange chromatography ; Inversion of elution order ; Micellar mobile phase ; Catecholamine ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 9 (1971), S. 723-728 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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