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  • 1
    Electronic Resource
    Electronic Resource
    Thermal decomposition and volatilization of poly(α-olefins)This paper was presented at the 15th Prague IUPAC Microsymposium, Prague, CSSR, July 21-24, 1975; Preprint A3. (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 1393-1402 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal decomposition of normal alkanes and linear poly(α-olefins) was found to occur predominately by random scissions, followed by volatilization into an open system. To show these processes the fragment distribution from high molecular weight linear polyethylene (fragments to C55), n-alkanes, polypropylene, and polyisobutylene (fragments to C60) are reported and discussed in depth. Based on the results, a mechanism of random scissions followed by volatilization is postulated for polyethylene and n-alkanes as well as for polyisobutylene and polypropylene. Polystyrene is shown not to follow the same mechanism, for little evidence for fragments above trimers was found. In addition, temperature rise-time measurements at the pyrolyzer probe are reported and explained.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170150610
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  • 2
    Electronic Resource
    Electronic Resource
    Pyrolysis and gas chromatography of plasma-polymerized ethyleneThis paper was a part of the presentation, Pyrolysis-Gas Chromatographic Analysis of Chain Branching in Polyethylene, at the 167th National American Chemical Society Meeting, Los Angeles, California, March 31-April 5, 1974. (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 1541-1544 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma-polymerized polyethylene (PPE) obtained on a radio-frequency glow discharge has been analyzed by flash pyrolysis combined with in-line hydrogenation and gas chromatography. The pyrogram of a bulk powder PPE, which had been characterized by both infrared spectroscopy and density measurements, was compared with a 400 Å thick PPE film deposited directly on the pyrolysis probe. Although the two pyrograms have a qualitative resemblance, they are substantially different from that of conventional branched polyethylene (PE). Some of the fragments exhibited by the deposited PPE are also present in pyrograms of 1,4-polybutadiene. It is evident that the deposited film is a highly branched and unsaturated network polymer with a random arrangement of these structural features.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.170130706
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  • 3
    Electronic Resource
    Electronic Resource
    Pyrolysis-gas chromatographic analysis of chain branching in polyethyleneThis paper was presented at the 167th National American Chemical Society Meeting, Los Angeles, California, March 31-April 5, 1974. (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 1515-1529 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A system with flash pyrolysis and gas chromatography (PGC) which includes in-line hydrogenation and packed columns is described. Under optimal conditions of temperature programming and flow rate, a high degree of resolution was obtained over a broad range of fragment lengths. The system has been applied to the analysis of side groups and long branches in polyethylene. It was found that, for low concentration of branches, yield and distribution of the isoalkanes is very sensitive to the type of polymerization used to form the polyethylene. A great number of the single-branched isoalkanes have been identified by comparing their retention time with the scale of respective boiling points and by pyrolyzing well characterized ethylene-propylene copolymers. The pyrograms of the ethylene-propylene copolymers demonstrated that a C—C bond in an α- or β-position to a tertiary carbon cleaves about two times more readily than a C—C bond in a linear chain. It was further found that the branch length of the side chain is indicated by the identity of the fragments produced, and the probability of formation of these fragments is directly related to the possibility of a cyclic decomposition mechanism. From the high yields of 3- and 5-methylalkanes it was possible to detect about 20 ethyl and 10 n-butyl branches per thousand in a low-density polyethylene. Thus, pyrolysisgas chromatography has to be considered seriously as a method for the determination of branches, even when in present in low concentration (Ziegler-type polyethylene).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.170130704
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