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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 156 (1988), S. 21-27 
    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 wurden Polyester basierend auf 1,4,5,6,7,7-Hexachlor-5-norbornen-2,3-dicarbonällureanhydrid (I), Tetrachlorphthalsäureanhydrid (II), Dibromneopentylglykol (II), ein Polyesterblend (V) bestehend aus dem Polyester (III) und einem Polyester (IV) für allgemeine Zwecke, ein Polyester (VI) basierend auf 1,4,5,6,7,7-Hexachlor-5-norbornen-2,3-dicarbonsäureanhydrid und dem Polyester III und ein Polyesterblend (VII) bestehend aus den Polyestern I und III hergestellt. Ihre chemische Resistenz und ihre Feuchtigkeitsaufnahme bei Temperaturen von 25 und 65°C wurden in Säuren, 20% NaOH und Wasser untersucht. Hierbei wurde gefunden, daß der Polyester (III) von den Säuren am wenigsten angegriffen wird. Verglichen mit unbehandelten Poly meren fand bei beiden Temperaturen in 20% NaOH eine Gewichtsabnahme bei allen Polyestern statt, mit Ausnahme des Polyesters VII. Erne Gewichtszunahme aller Polyester wurde beobachtet durch Feuchtigkeitsaufnahme sowohl bei 25 als auch bei 65°C, wobei die Zunahme bei der höheren Temperatur größer war. Der Polyester III zeigte die geringste Feuchtigkeitsaufnahme.
    Notes: Chlorendic anhydride based polyester (I,) tetrachlorophthalic anhydride based polyester (II), dibromoneopentyl glycol based polyester (III,) general purpose polyester (IV,) blend of dibromoneopentyl glycol based polyester with general purpose polyester (V,) chlorendic anhydride and dibromoneopentyl glycol based polyester (VI), and a blend of chlorendic anhydride based polyester and dibromoneopentyl glycol based polyester (VII) were prepared and their chemical resistance and moisture absorption studied in various reagents, acid, alkali, and water, at 25 and 65°C. It is found that the polyester (III) is the least affected in the presence of the acids. In 20% NaOH, there was a decrease in weight for all polyesters at both the temperatures compared to the control except the polyester (VII). Increase in weight of all the polyesters was observed during the absorption of moisture both at 25 and 65°C. The increase was higher at higher temperature. Polyester (III) thus shows the least absorption of moisture.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 1901-1908 
    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: Thermal behavior and degradation mechanisms of three polyester resins, namely bisphenol A based, isophthalic acid based, and general purpose were studied. These resins were cured with styrene in the presence of benzoyl peroxide (BPO) and methyl ethyl ketone peroxide (MEKP) as initiators. The cured resins were studied by thermogravimetric analysis and mass spectrometry. From the thermogravimetric data it was observed that the cured bisphenol-A-based polyester resin was thermally more stable than the cured isophthalic acid-based and general purpose polyester resins. It was also observed that polyester resins cured with MEKP are thermally more stable than benzoyl peroxide-cured products. Thermogravimetric analysis data shows that there are two first-order degradation reactions during thermal degradation in nitrogen atmosphere. The first degradation step involves the scission of cross-links/weak links with the liberation of free linear chains. The second step involves a random scission of the free linear chains into smaller fragments. The framentation patterns of the polyester resins were identified by mass spectrometery. Possible mechanisms for the degradation of the cured polyesters accounting for the experimental observations are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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