ISSN:
0098-1273
Schlagwort(e):
Physics
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The role of the intrinsic viscosity [η] as separation parameter in gel permeation chromatography (GPC) was studied for dextrans (from Leuconostoc mesenteroids B512) dissolved in water with deactivated silicagel (Porasil) as the column-filling material. For that purpose specific viscosities of dextran fractions eluted by GPC were measured as a function of the elution volume v. Provided that the elution volumes are corrected for zonal spreading, they are related to the intrinsic viscosities in an unambiguous way, probably reflecting a unique relationship between degree of branching and molecular weights. This was further investigated by developing an iteration method to prepare two calibration curves γ(v) and g(v), respectively, relating ln[\documentclass{article}\pagestyle{empty}\begin{document}$\left[ {\bar \eta } \right]$\end {document}] and InM (M is the molecular weight) to v. It required that the weight-average molecular weight Mw, the number-average molecular weight Mn, and the average intrinsic viscosity [\documentclass{article}\pagestyle{empty}\begin{document}$\left[ {\bar \eta } \right]$\end {document}] for a number of dextran samples (broad distributions) be previously known. The calibration curves found lead to consistent values of the above-mentioned averages. Moreover, they allow-establishment of the [\documentclass{article}\pagestyle{empty}\begin{document}$\left[ {\bar \eta } \right]$\end {document}]-M relationship over the range 5000 〈 M 〈 500,000.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pol.1978.180161205
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