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  • 1965-1969  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Poly(chloroaldehydes). II. Polymerization of chloralParts of this paper were presented before the Division of Polymer Chemistry at the 148th National Meeting of the American Chemical Society, Chicago, September 1964. (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 1545-1552 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Chloral was polymerized by means of cationic and anionic initiators and the products compared. Anionic catalysts readily produce high molecular weight polymer (DP ∼ 300-600), but a DP of only 200 could be produced with cationic catalysts. The anionic system apparently initiates and propagates polymerization much more readily than the cationic system. This effect is attributed to the inductive effects of the chlorine atoms on the chloral. Little difference was found when products of similar DP were compared as to x-ray diffraction pattern, infrared spectrum and tractability. This is believed due to the single type of structure which is sterically favored. Various cyclic compounds of chloral could not be made to undergo polymerization under cationic initiation. The conditions required to effect ring opening were too rigorous to enable polymerization to take place.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030422
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Poly(chloroaldehydes). III. Poly(dichloroacetaldehyde) (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 3741-3751 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Although dichloroacetaldehyde has only one chlorine less than chloral, the polymerization and polymer characteristics are quite different. Dichloroacetaldehyde is readily polymerized by Lewis acid catalysts to polymer with terminal hydroxyl groups. The catalyst BF3·Et2O, at 0°C., produces very high molecular weight polymer, in bulk polymerization. A DPn of about 400 is readily attainable. The characteristics of the polymerization indicate a cationic type, with greater dependence of DP upon chain termination rather than chain transfer. The polymer is readily end-capped by acetic anhydride, with a pyridine catalyst, to increase its thermal stability. Melting point, infrared spectra, and x-ray diffraction measurements confirm that the polymer produced under these conditions is amorphous. Cast films of the polymer could be only partially oriented The polymer is soluble in many common organic solvents.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100031106
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Poly(chloroaldehydes). I. Polychloral stabilizationPresented before the Division of Polymer Chemistry at the 148th National Meeting of the American Chemical Society, Chicago, September 1964. (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 1535-1543 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polychloral diol, unlike polyoxymethylene diol, is not readily capped in the presence of alkali catalysts. Polychloral is capped under acid conditions by acid anhydrides and chlorides and does not appear to undergo degradation during the process. Evidence for end-capping is provided by infrared analysis in the case of the low DP polychloral, metachloral. End-capped polychlorals possess good stability towards hot dimethylformamide and good stability at elevated temperatures (255°C.). From the melting points of copolymers, polychloral itself is estimated to have a melting point of about 460°C. The high melting point is consistent with the rigidity of the polymer chain. A means of estimating the DP of the polymer is proposed, based on a form of endgroup analysis. By this technique, metachloral is estimated to have a DP of about 50.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030421
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    Paper (German National Licenses)
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