Viscoelastic properties of Na-carboxymethylcellulose solutions

Abstract

The rheological characteristics of 5% solutions of Na-carboxymethylcellulose (CMC)I of various origin were investigated. Depending on the molar mass (1.25-1.94 x 10(5) g mol(-1)), i.e., the degree of polymerization (545-851) and degree of substitution (0.748-1.039), as well as the electrolyte (NaCl) content (0.55-36.40%), it was found that microgel particles appear in some cases, while in other cases there are entanglements or isolated particles of CMC macromolecules in solution. Stronger macromolecular interactions were observed when the degree of polymerization was greater than about 600 and the degree of substitution was higher than approximately 0.8. The rheological characteristics of the investigated samples are discussed in relation to the macromolecular structure (defined by X-ray powder diffraction and FT-IR spectroscopy) in the solid state.