ISSN:
0006-3525
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Poly A was found to precipitate upon freezing acidic solutions at pH values where it is normally soluble; this precipitate tends to have the form of small thin plates of irregular outline (“plates”). The X-ray diffraction pattern and solubility properties of the “plates” were compared with those of poly A precipitated solely by exposure to lower pH values, and with fibers drawn from acidic solution. There is considerable molecular order in each of these three types of preparation. In all cases, the diffraction patterns are consistent with the presence of the double-stranded helical structure proposed by Rich, Davies, Crick, and Watson (J. Mol. Biol., 3, 71 (1961)) based on fiber diffraction data. The diffraction pattern from the “plates” is compared in detail with that of the fibers, and is shown to be in accord with a packing scheme having the chain axis of the molecular structure confined to the plane of the “plate,” but oriented randomly in that plane.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/bip.1972.360110914
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