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  • Polymer and Materials Science  (4)
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  • 1
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The inclusion copolymerization of various vinyl monomer systems was studied in a thiourea and perhydrotriphenylene matrix while that of a disubstituted butadiene system was investigated in canals of thiourea, perhydrotriphenylene, deoxycholic acid and β-cyclodextrine. The results were compared with those obtained for the corresponding free copolymerization especially with regard to copolymer composition. In all vinyl monomer systems inclusion copolymerization leads to the same copolymer composition as is found in the free process. On the other hand, in case of the diene system, the copolymer composition of the inclusion products is remarkably different from that of the copolymers formed by the free reaction; the former is always nearly ideal statistic independent of the nature of the host. Inclusion homopolymerization can successfully be carried out with monomers where the free radical polymerization is prevented by allylic inhibition.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 1645-1656 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radiation induced copolymerization of chlorotrifluoro ethylene (CTFE) with various butenes was studied at temperatures between -20°C and +40°C using 60Co-γ rays.In the case of isobutene (IB) an almost alternating crystalline copolymer is formed in a heterogeneous reaction. At high IB-concentrations a cationic homopolymerization of this olefin occurs simultaneously to the radical copolymerization. The copolymerization rate increases with increasing temperature and degree of conversion. The highest rates are obtained for monomer mixtures with about 80 to 90 mole % CTFE. The decrease in rate for monomer mixtures with still higher CTFE concentrations is assumed to be partly due to the low IB-concentration and partly to degradative chain transfer by the isobutene. In support of this assumption molecular weights and melting points of the copolymer have been determined.Similar results were obtained for butene-1 but in this case, no cationic homopolymerization was observed and the reaction proceeded homogeneously.Cis- and trans-butene-2 only acted as polymerization inhibitors.
    Additional Material: 12 Ill.
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  • 3
    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: Vinylchloride and styrene were copolymerized with 60Co-γ-rays in the temperature range from -78 to 50°C. The dependence of copolymer composition on temperature and composition of the monomer mixture was studied. The formal copolymerization parameters were determined and IR-studies were carried out to obtain qualitative information on the distribution of the monomer units in the copolymers formed under different conditions. From the results obtained, it is concluded that the copolymerization at temperatures from -78 to +20°C is partly due to a radical mechanism, partly to an ionic reaction.
    Notes: Vinylchlorid und Styrol wurden bei Temperaturen zwischen -78 und 50°C durch 60Co-γ-Strahlung copolymerisiert. Die Zusammensetzung der Copolymeren wurde in Abhängigkeit von der Temperatur und der Zusammensetzung des Monomergemisches bestimmt. Die formalen Copolymerisationsparameter wurden berechnet, und es wurde versucht, aus den IR-Spektren der Copolymeren qualitative Aussagen über die Verteilung der Monomereinheiten in den unter verschiedenen Bedingungen hergestellten Copolymeren zu machen. Die Ergebnisse weisen darauf hin, daß die Copolymerisation bei Temperaturen von -78 bis +20°C teilweise nach einem radikalischen, teilweise nach einem ionischen Mechanismus verläuft.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: If one considers CD spectra as vectors, then a CD spectrum may be treated as a single parameter, every wavelength entering with the same weight. The representation of a set of spectra as a vector space and the problem of the linear independence of the concentrations are discussed. Three examples of vectorial interpretation are given: determination of the number of independent molecular species; determination of the stoichiometry of a complex; and graphical representation of the overall variation of a spectrum as a function of an external parameter.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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