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  • Electronic Resource  (5)
  • 1985-1989  (5)
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  • Electronic Resource  (5)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 33 (1988), S. 1225-1229 
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Thermochemische Umwandlungen einiger Polyimide, die durch Polykondensation der Dianhydride alicyclischer Tetracarbonsäuren mit 4,4′-Diaminodiphenyloxid dargestellt waren, wurden durch verschiedene thermoanalytische Methoden (TG, massenspektrometrische EGA und Pyrolyse-Gaschromatographie) untersucht. Die thermische Spaltung der Dianhydrid-Komponente nach einer Retro-Diensynthese ist die Hauptreaktion, die die thermische Stabilität der Polymeren bestimmt. Bei Abwesenheit der endo-Ethylen-Bindung in der Dianhydrid-Komponente oder Substitution durch eine Etherbindung wird die thermische Stabilität von Polyimiden mit alicyclischen Baugruppen erhöht.
    Abstract: РЕжУМЕ тЕРМИЧЕскИМИ МЕтОДА МИ АНАлИжА, МАсс-спЕктРОМЕтРИЧЕ скИМ АВг И пИРОлИжНОИ гАжОВОИ хРОМАтОгРАФИЕИ ИжУЧ ЕНы тЕРМОхИМИЧЕскИЕ пРЕВРАЩЕНИь пОлИИМИДОВ, пОлУЧЕНН ых РЕАкцИЕИ пОлИкОНДЕНсАцИИ ДИА НгИДРИДОВ АпИцИклИЧ ЕскИх тЕтРАкАРБОНОВых кИс лОт И 4,4-ДИАМИНОДИФЕНИл ОксИДА. тЕРМИЧЕскАь ДИссОцИ АцИь ДИАНгИДРИДНых Ф РАгМЕНтОВ, сООтВЕтстВУУЩАь ОБР АтНОИ РЕАкцИИ РЕтРОДИЕНОВ ОгО сИНтЕжА, ьВльЕтсь ОсНОВНОИ РЕАкцИЕИ ОпРЕДЕльУЩ ЕИ тЕРМОУстОИЧИВОст ь ИжУЧЕННых пОлИМЕРОВ. пОкАжАНО, ЧтО ОтсУтст ВИЕ ЁНДО-ЁтИлЕНОВОИ сВьж И ИлИ жАМЕЩЕНИЕ ЕЕ кИслОРОДОМ В ДИАНг ИДРИДНых ФРАгМЕНтАх, пРИВОлИт к УВЕлИЧЕНИУ тЕРМОУст ОИЧИВОстИ пОлИИМИДОВ.
    Notes: Abstract The thermochemical conversions of certain polyimides obtained by the polycondensation of dianhydrides of alicyclic tetracarboxylic acids and 4,4-diaminodiphenyl oxide were studied by different methods of thermal analysis (thermogravimetry, mass-spectrometric evolved gas analysis, and pyrolytic gas chromatography). The thermal dissociation of dianhydride fragments according to the reverse reaction of retrodiene synthesis is the basic reaction that determines the thermal stabilities of the polymers studied. It is shown that the absence of endoethylene bonding or its substitution by oxygen in the dianhydride fragments leads to increases in the thermal stabilities of alicyclic polyimides.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical chemistry journal 20 (1986), S. 558-561 
    ISSN: 1573-9031
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Fire and Materials 10 (1986), S. 133-135 
    ISSN: 0308-0501
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Penetration of the carbonized polymeric residues has been investigated and their influence on combustibility of polymers has been shown. It has been found that filtration of liquid and gas products of pyrolysis through the carbonized layer upon combustion is described by Darcy's law, the movement of liquids being due to the surface tension forces. It has been shown that the carbonized layer cannot be regarded as an important obstacle for passing of volatile and low-viscous products into the gas phase, and that the polymeric melts can also rise through the coke due to the capillary forces. Phosphoric and some boric compounds have been found to cause a decrease in penetration of the carbonized residues, which can be one of the reasons of the flammability decrease of polymers when using such compounds.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 39 (1988), S. 434-437 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch die Untersuchung des Phasenverhaltens von Dioxanlösungen der Polyamidosäuren (PAS) auf Basis wenig aktiver Dianhydride der Tricyclodecentetracarbonsäure wurden die Bedingungen für die Existenz der PAS im mesomorphen Zustand ermittelt. Unter diesen Bedingungen wurde ein starkes Anwachsen der PAS-Ketten festgestellt. Der Polymerisationsgrad nahm von 7 auf 90 zu; die Grenzviskosität der Polymere stieg von 0,1 dl/g auf 1,2 dl/g.
    Notes: The study of the peculiarities of the phase behaviour of solutions of poly(amic acids) (PAA) on the basis of low-active dianhydride of tricyclodecentetracarboxylic acid in dioxane permitted to establish the conditions of their existence in the mesomorphic state. Under these conditions an intensive growth of the PAA chains was observed, the polymerization degree increased from 7 up to 90, and the intrinsic viscosity of the polymers increased from 0.1 up to 1.2 dl/g.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 39 (1988), S. 443-445 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die heterogene Chelation von Polyamidosäure- und Polyimid-Fasern und -Filmen durch Co2+-, Ni2+, Zn2+-, Cu2+- und Ag+-Ionen wird untersucht. Es wird gezeigt, daß die Einführung von Übergangsmetallionen eine Verfärbung und Festigkeitszunahme der genannten Polymere bewirkt.
    Notes: The heterogeneous process of chelation of poly(amic acid) and polyimide fibres and films by Co2+, Ni2+, Zn2+, Cu2+ and Ag1+ ions is studied. Introduction of transition metal ions is shown to cause colouring and to increase the strength of the above polymer materials.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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