The Properties of Water in Macromolecular Gels. VI. The Relationship between the Rheological Properties and the States of Water in Macromolecular Gels

Abstract

The relationship between the rheological properties and the states of water in macromolecular gels is investigated by both the rheological and nuclear magnetic resonance methods. In accordance with the stress-strain curve, macromolecular gels are shown to be classifiable into: (1) an agarose type of gel which shows great gel strength and brittleness at breaking; (2) a κ-carrageenan type of gel showing great gel strength, but ductility at breaking, and (3) a λ-carrageenan type of gel, which has very little gel strength and is pasty. The dependence of the NMR line-width of water in gels on the polymer concentration and on the temperature reveals that the motional state of water in gels is restricted in this order: the agarose type of gel>the κ-carrageenan type of gel>the λ-carrageenan type of gel. These results show that the state of water is closely related with the rheological properties of macromolecular gels.

Crystal Growth in Gels from the Mechanisms of Crystal Growth to Control of Polymorphism: New Trends on Theoretical and Experimental Aspects

“…However, if the pore size is small enough, there is a possibility that a higher supersaturation is needed, due to the compartmentalization of solvents. Finally, this may also represent an effect in the diffusion of substances [69][70][71].…”

Rheology of Gels

“…It was suggested that the gel contained junction zones of various strength and that the stronger junction zones are responsible for the equilibrium stress and the high elastic recovery. Aizawa et al (1973) have suggested that there is a correlation between the rheological properties of polysaccharide gels and the state of water in the gel as determined by NMR. The stress-strain curves obtained by these workers for agarose, lambda-carrageenan, kappa-carrageenan and the bacterial polysaccharide curdlan are shown in Figure 2.…”