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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Inorganica Chimica Acta 21 (1977), S. 47-49 
    ISSN: 0020-1693
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0013-4686
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Electrochimica Acta 37 (1992), S. 1559-1564 
    ISSN: 0013-4686
    Keywords: comb-like polymers ; ionic conductivity ; lithium perchlorate ; polyepoxides ; polymer electrolytes
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Organometallic Chemistry 177 (1979), S. 313-321 
    ISSN: 0022-328X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Solid State Ionics 72 (1994), S. 140-146 
    ISSN: 0167-2738
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 933-938 
    ISSN: 0887-6266
    Keywords: liquid-crystal copolyesters ; melt-spinning ; mechanical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Melt-spinning and mechanical properties of fibers of a new class of semirigid thermotropic liquid-crystal polymers are presented. These copolyesters are synthesized from 4-4′-dihydroxybiphenyl (B), 4-hydroxybenzoic acid (H), and flexible units provided by aliphatic diacids. The flexible units depress the melting temperature without strongly depressing the mechanical properties. These liquid-crystal polymers can be easily spun at high draw ratios. Indeed, unlike rigid liquid-crystal polymers, relatively high draw ratios are needed to attain high mechanical strength. Tensile moduli of about 28 GPa and tensile strengths of about 350 MPa are obtained. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 1209-1232 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The terpolymerization of ethylene, propylene, and methylcyclopentadienyl-5-endonorborn-2-enylmethane (III) by means of different vanadium-based coordination catalysts was investigated. The structure of III and its isomeric composition was studied by using vapor-phase chromatography, mass spectrometry, and NMR, infrared, and ultraviolet spectroscopy. The catalyst system V Acac3-Et2AlCl was used under different conditions, and the influence of several variables regulating the terpolymerization process were related to the properties of the resulting terpolymers (EPTM). The insertion of III into EPTM chains takes place randomly and does not influence the random distribution of comonomers. The selective opening of the norbornene double bond of III has been demonstrated by use of 2,3-dihydro-III as model compound. Tritiated III gave a radiochemical titer of unsaturation in excellent agreement with the value deduced from ultraviolet measurements. The influence of Lewis bases added to VAcac3-Et2AlCl catalyst is discussed.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es werden zwei Hypothesen aufgestellt zur Bildung von Vinyldoppelbindungen in Polypropylenen, die durch anionisch-koordinative Polymerisation bei Temperaturen oberhalb von 80°C erhalten werden.Gemäß der ersten Hypothese entstehen diese Vinyldoppelbindungen infolge eines Abbruchsprozesses, bei dem eines der Wasserstoffatome der Methylgruppe des Propylens an das wachsende Makromolekül angelagert wird, während sich die verbleibende Allylgruppe mit dem Katalysatorkomplex vereinigt.Die entstandene Metall-Allylbindung könnte dann ein neues Makromolekül starten, das als Endgruppe eine Vinyldoppelbindung tragen würde. Einige experimentelle Ergebnisse, die die Gültigkeit dieser Hypothese bestätigen, werden mitgeteilt.Anschließend wird eine weitere Hypothese diskutiert, die auf den von K. ZIEGLER und Mitarb. bei der Pyrolyse einiger Isoalkyl-aluminium-Verbindungen erhaltenen Ergebnisse beruht.
    Notes: Two hypothesis are proposed on the formation of vinyl double bonds in polypropylenes obtained in anionic coordination polymerization at temperatures above 100°C.According to the first hypothesis, the vinyl double bonds originate from a termination mechanism during which one of the hydrogen atoms in the methyl group of propylene combines with the growing macromolecule, while the remaining allyl group combines with the catalytic complex. The metal-allyl bond could thus bring about a new macromolecule containing a vinyl double bond as terminal group. Some experimental evidence supporting this hypothesis are examined.Afterwards, an other hypothesis, based on the results obtained by K. ZIEGLER and coworker on pyrolyzing some isoalkylaluminum compounds has been discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: 1-Isopropyliden-3a.4.7.7a-tetrahydroinden (I) kann mit äthylen und Propylen durch anionisch-koordinative Vanadin-Katalysatoren terpolymerisiert und mit äthylen copolymerisiert werden. Für die Polymeren werden die IR-, NMR- und UV-spektroskopischen Daten sowie die Molekulargewichtsverteilungen mitgeteilt.Der Einbau von I verläuft hauptsächlich über die öffnung der Cyclohexendoppelbindung. Im allgemeinen beträgt der Gehalt an I weniger als 10 Mol-%.Versuche, Homopolymere von I und Copolymere aus Propylen und I mit diesem Katalysatortyp zu erhalten, waren ohne Erfolg.Mit radikalischen oder mit anionischen Katalysatoren konnte aus I kein festes Polymeres erhalten werden. Lediglich mit AIBN wurden Oligomere erhalten, die Isobuttersäurenitrilgruppen, gebunden an das System der konjugierten Doppelbindungen, enthielten. In flüssigem Ammoniak gelöst, reagiert K oder KNH2 mit I in äquimolekularen Mengen zu wachsartigen Produkten, die keine NH2-Gruppen enthalten. Mit K werden Dihydroderivate von I gebildet.Die Ergebnisse lassen sich durch die Annahme erklären, daß sich aus I stabilisierte Radikale und Anionen bilden, die nicht zum Wachstum befähigt sind.
    Notes: By means of vanadium based anionic coordinate catalysts 1-isopropylidene-3a.4.7.7a-tetrahydroindene (I) can be terpolymerized with ethylene and propylene and copolymerized with ethylene. IR, NMR, UV spectroscopic data, and mol. wt. distributions are reported for the polymers.The incorporation of I is predominantly by opening of the cyclohexene double bond. The content of I was generally less than 10 mole-%.Attempts to obtain homopolymers of I and copolymers of propylene and I with this type of catalyst were unsuccessfull.No solid polymer could be produced from I by free radical or anionic catalysts. With AIBN only oligomers were obtained which had cyanoisobutyric groups attached to the conjugated double bond system. K or KNH2 in ammonia solution react with I in equimolar ratios to give waxy products which do not contain NH2 groups. With K di-hydrogenated derivatives of I are formed.The results have been interpreted in terms of stabilized radicals and anions derived from I which are unable to propagate.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 136 (1970), S. 23-45 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: 1-Isopropyliden-3a.4.7.7a-tetrahydroinden (I) liefert mit verschiedenen kationischen Katalysatoren in einem weiten Temperaturbereich ein Homopolymeres, und zwar werden amorphe Produkte mit mittleren Molekulargewichten zwischen 1000 und 17000 erhalten. Die IR-, NMR- und UV-Spektren beweisen, daß die Polymerisation unter 1.4-Öffnung des konjugierten Doppelbindungssystems verläuft. Ein α-Wert von 0,68 in der KUHN-MARK-HOUWINK-Gleichung und die Anwesenheit zweier Doppelbindungen pro Grundbaustein deuten auf eine lineare Struktur der Produkte.Das Katalysatorsystem (CH3)3CCl/(C2H5)2AlCl wurde besonders eingehend untersucht. Die besten Ergebnisse werden bei Molverhältnissen von (CH3)3CCl/(C2H5)2AlCl ≥ 3 erhalten. Während der Reaktion wird der Cokatalysator verbraucht. Toluol wird durch dieses Katalysatorsystem noch bei -78°C alkyliert. Die Polymerisationstemperatur hat keinen nachweisbaren Einfluß auf die Struktur der Polymeren. Aus der Abhängigkeit von log \documentclass{article}\pagestyle{empty}\begin{document}$$\overline {DP}$$\end{document} von 1/T wurde eine Aktivierungsenergie Eapp von -3,23 kcal/mol gefunden.Die Polymeren enthalten wenig Chlor. Wird Toluol als Lösungsmittel verwendet, dann enthalten die Produkte auch Spuren aromatischer Ringe. In keinem Fall jedoch konnten OH-Gruppen nachgewiesen werden. Diese Ergebnisse werden diskutiert, und zwar unter Berücksichtigung der Nukleophilie von (I) und der pKa-Werte der initiierenden Carboniumionen, die sich ausgehend von (I) formulieren lassen.
    Notes: By means of different cationic catalysts 1-isopropylidene-3a.4.7.7a-tetrahydroindene (I) can be homopolymerized in a wide range of temperatures.Amorphous polymers having \documentclass{article}\pagestyle{empty}\begin{document}$$\overline {MW}$$\end{document} in the range 1,000-17,000 were obtained. IR, NMR, and UV data indicate the 1.4-opening of the conjugated double bond system of (I). An α value of 0.68 in the KUHN-MARK-HOUWINK equation and the presence of two double bond for every repeating unit support the linear structure of the polymers obtained.The system Me3CCl/Et2AlCl was investigated. The co-catalyst was consumed during the polymerization. The best yields were observed for values of the molar ratio Me3CCl/Et2AlCl ≥ 3. A strong alkylating ability of this catalyst toward toluene was found even at -78°C. No substantial structural differences were observed in the polymers obtained at different temperatures. Eapp = -3.23 kcal/mole was calculated from the log \documentclass{article}\pagestyle{empty}\begin{document}$$\overline {DP}$$\end{document} vs. 1/T plot.Chlorine was found in the polymer; traces of aromatic rings were present when the polymerization was carried out in toluene; no hydroxyl groups were detected.The results obtained are discussed in terms of the nucleophilicity of (I) and of the pKa values of the initial carbonium ions derived from (I).
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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