Physicochemical properties and compatibility of sodium alginate and fucoidan solutions.

The interaction between linear sodium alginate and branched fucoidan were investigated using viscosity and tensiometric measurements. It was shown that water-soluble interpolymer complex is formed. The alginate-fucoidan complexation is due to the formation of a cooperative system of hydrogen bonds between the ionogenic and hidroxyl groups of sodium alginate and fucoidan and hydrophobic interactions. The intensity of the polysaccharide-polysaccharide interaction increases with an increase in the content of fucoidan in the blend. It was established that alginate and fucoidan are weak surfactants of the associative type. The surface activity of fucoidan was 34.6 mN∙m/mol, and for alginate was 20.7 mN∙m/mol. The resulting alginate-fucoidan interpolymer complex exhibits high surface activity and indicates a synergistic effect of combining two polysaccharides. The values of the activation energy of the viscous flow process were 7.0 kJ∙mol, 16.2 for kJ∙mol and 33.9 kJ∙molfor alginate, fucoidan and their blend, respectively. These studies provide a methodological basis for determining the conditions for preparation of homogeneous film materials with a certain complex of physico-chemical and mechanical properties.