Viscosity of 25% solutions of cellulose acetate versus intrinsic viscosity distribution

The 25% w/w solutions of blends of cellulose acetate fractions have higher viscosities than solutions of single fractions of the same average intrinsic viscosity. It was found that the viscosity of a blend can be related to its composition by the relationship: where {article}{empty}{document}[ η ]25%{document} is the apparent intrinsic viscosity of the cellulose acetate blend in solution at 25% concentration, and [η] i are the intrinsic viscosities of the components. By application of this equation it was determined that only a portion of the high anomalous viscosity of solutions of cellulose acetate prepared from viscose grade wood pulp could be attributed to intrinsic viscosity distribution.