| Abstract: | Laboratory-made samples of the polysaccharide xylinan, also called acetan, were studied in aqueous solution at various ionic strengths I (0.01 mol/L ≤ I ≤ 0.30 mol/L). The conditions for clarification (ultracentrifugation/membrane filtration) were studied. The Zimm procedure was used to obtain the average molar mass, the second virial coefficient, and the radius of gyration. The interpretation of the angular dependence of scattered light by fitting with “Master Curves” led to double-stranded wormlike chains with persistence lengths between 90 and 120 nm. The ionic strength had a strong effect on the thermodynamic second virial coefficient, but the overall structure remained unchanged. The ambiguity of the light scattering data was discussed assuming alternatively a two-component system instead of the wormlike chain model for the experimental scattering curves. The two-component system can be ruled out on the basis of model calculations. © 1996 John Wiley & Sons, Inc. |
