Solution properties of the acrylamide-modified cellulose polyelectrolytes in aqueous solutions

A novel cellulose-based polyelectrolyte (AM-C) containing acylamino (DS = 0.625) and carboxyl (DS = 0.148) groups was homogeneously synthesized from cellulose with acrylamide in NaOH/urea aqueous solutions. Solution properties of AM-C in aqueous solutions were investigated by laser light scattering, rheometry, and viscometry. The results indicated that AM-C could form large aggregates spontaneously in water with or without the addition of salts by the strong hydrogen bonds and electrostatic interaction between acylamino and carboxyl groups. Steady-shear flow study showed a Newtonian behavior of the solutions in the dilute regime while a shear-thinning behavior as the concentration increases. The critical concentration (ce) for transition from dilute to concentrated solution was determined to be 0.7 wt %. Aqueous solutions of AM-C displayed good thermo-stability, reversible liquid-like characters attributing to the chemical modification. The derivation from Cox–Merz rule at relatively low concentration was related to the co-existence of single chain and large aggregates of AM-C in dilute regime. As the polymer concentration increased, the AM-C system was transformed into a homogeneous entanglement structure, resulting in the disappearance of deviations from the Cox–Merz rule.

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