Aggregate structure and rheological properties of mercerized cellulose / LiCl·DMAc solution

The effect of mercerization on the cellulose solution was investigated in terms of rheological and dilute solution properties in 8 wt % LiCl/N,N-dmiethylacetamide (DMAc). Cotton lint, cotton linter, and dissolving pulp were used for native cellulose samples. Static light scattering (SLS) measurements show that the second virial coefficient, A₂, of the cellulose solutions decreased by the mercerization, indicating that the affinity between cellulose and the solvent molecules decreased by the mercerization. A long time relaxation was found only for the mercerized cellulose solution by viscoelastic measurements for semidilute solutions. This indicates that some heterogeneous structures were formed in the mercerized cellulose solution. Some aggregate structures, which have slow decay time, were observed in the 0.5 wt % mercerized cellulose solution by dynamic light scattering (DLS) measurements. According to these results, the low affinity between cellulose and the solvent makes some aggregate structures in the mercerized cellulose solutions in 8 wt % LiCl·DMAc above the overlap concentration.