Depolarization of scattered light in solutions of linear and branched polysaccharides

Abstract

The effect of branching on the depolarization of light scattered from polymer solutions has been investigated employing various branched and unbranched polysaccharides. Two dextran fractions of M̅_w 71,000 and 131 × 10⁶ were studied in a strong solvent (aqueous KOH) and an indifferent solvent (water). The other polymers, studied in aqueous KOH only, included unfractionated corn amylopectin, the β-amylase limit dextrin of corn amylopectin, unfractionated corn amylose, and three subfractions of potato amylose (M̅_w = 2.4 × 10⁶, 1.14 × 10⁶, and 0.27 × 10⁶). Each polymer system was studied at several concentrations and all components of the scattered light, namely H_u, V_u, H_u, V_u, H_u and V_u, were measured in each case. In general the results are in agreement with predictions of Krishnan and of Doty. However, certain important deviations from predicted behavior are noted and discussed.