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  • 1985-1989  (2)
  • 1905-1909
  • Polymer and Materials Science  (2)
  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2491-2500 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Linters cellulose was degraded in an inert and water-free atmosphere using thermic and ultrasonic energy. The fragments were nitrated and fractionated by precipitation. A mathematical analysis of the degree of polymerization (DP) values of the differential and individual fractions resulted in a common denominator of 40 for all DPs of degraded celluloses. Also, the value of 120 occurs very frequently. Similar results were found for a series of 33 industrial pulps and some other celluloses. The smallest units in higher molecular-weight celluloses are multiples of 40 or 120 in the range of 360 to 720. The results and the calculations of this study suggest that preformed substructures obviously exist in the cellulose of higher plants which are independent of the origin of the cellulose. The sizes of the resistant substructures seem to be independent of the kind of degradation applied.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: PETP samples were crystallized in different manner, and the resulting lamellar structures were investigated by X-ray diffraction, DSC, NMR, und Raman spectroscopy. In dependence on the crystallization conditions, lamellar thicknesses between 1.5nm and 2.5nm, rigid amorphous regions (interface) of about 2nm, and mobile amorphous regions with 1 nm to 3 nm were obtained. In the latter ones the rearrangement processes take place which are connected with the thermal glass transition. The thicknesses of these regions are related to the correlation length of the rearrangement processes determined via the glass transitions.
    Notes: Mit Röntgenbeugungs-, kalorimetrischen, NMR- und ramanspektroskopischen Untersuchungen werden Aussagen zur lamellaren Struktur von unterschiedlich kristallisierten PETP-Proben gemacht. Die verwendeten Kristallisations-regime ergeben Lamellendicken von 1,5 nm bis 2,5 nm, starre amorphe Bereiche (Randschichten) von etwa 2 nm und beweglich amorphe Bereiche von 1 nm bis 3 nm, in denen die mit dem thermischen Glasübergang verknüpften Umlagerungsprozesse ablaufen. Die Dicke dieser Bereiche entspricht den aus den Glasübergängen ermittelten Korrelationslängen der Umlagerungsprozesse.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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