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  • Polymer and Materials Science  (3)
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  • 1
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acyl perchlorates generated in styrene without a solvent by acyl chlorides and silver perchlorate gave polystyrenes with covalently bonded acyl groups. In order to gain secured values their number average relative molecular masses (M̄n) were determined by different methods. The polystyrenes could be hydrogenated with hydrogen and Raney nickel at room temperature and under atmospheric pressure without attacking the phenolic nuclei. In addition IR data and a UV absorption at 294 nm of the polystyrenes revealed the presence of and olefinic bond, which was also found in a polystyrene obtained by polymerisation with perchloric acid. Also the quantitative evaluation of the hydrogeneation by UV absorption data gave number average relative molecular masses (M̄n,H), which are in accordance with other M̄n values. Furthermore, the UV absorption data of the polystyrenes gave correct M̄n values (M̄n,e) in combination with the molar absorption coefficients (ε) of model compounds. The number of covalently bonded acyl groups in a polystyrene sample could be determined by quantitative measurement of the UV absorption in combination with the ε-values of model compounds and the M̄n values. This number was found to depend on the nature of the acyl perchlorate and it amounts to one acyl containing molecule per four to hundred molecules without an acyl group.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of styrene was found not to take place with 4-phenylazobenzoyl perchlorate in benzene solution. 4-Biphenylcarbonyl perchlorate, however, initiates styrene polymerization under the same conditions leading to a product not containing acyl groups as indicated by UV spectroscopic analysis. 4-Phenylazobenzoyl, 2-naphthoyl, and 9,10-dioxo-2-anthracenecarbonyl perchlorate (6b, 7b, and 8b), prepared form silver perchlorate and the corresponding acyl chlorides 6a, 7a, and 8a in styrene, were found to initiate the polymerization of styrene under anhydrous conditions at -25°C in the dark. By UV spectroscopy it could be shown that the resulting polymers contain covalently bound acyl groups. Their absorption bands correspond to those of model compounds 6c, 7c, 8c, and 7d, respectively. IR spectra of mixtures of polystyrene with model compounds show that incorporation of acyl groups can be detected by their carbonyl absorption in the region of 1680 - 1700 Cm-1 only in polystyrenes having molar masses 〈50 000.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 14 (1976), S. 609-615 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Styrene was polymerized in bulk for 45 min at 70°C under a nitrogen atmosphere to a conversion of 6.16 weight-percent with an aliphatic azo compound, which contained four p-methoxyphenyl groups per molecule. The polystyrene could be purified easily by column chromatography and was then free of initiator and its decomposing products. It was separated into ten fractions by fractional precipitation (toluene/methanol), and the molecular weights of the polystyrenes were determined osmotically. The ultraviolet absorptions of the polystyrene solutions in dioxane were optically constant and followed the Bouguer-Lambert-Beer law. This made it possible to determine the number of absorbing groups per polystyrene molecule, which were constant with a value of 2. Polystyrenes with a number average molecular weight to 106 should be determinable in the same way.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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