Rheology of cellulosic N-methylmorpholine oxide monohydrate solutions of different degrees of polymerization

Preparation and shear and elongational rheology of cellulose solutions of d ifferent degrees of polymerization (DP) in N-methylmorpholine oxide monohyd rate (lyocell) were investigated. The dissolution process takes place in tw o stages, depending on the content of low and high DP fractions from the di ssolving pulp blends. The influence of the DP of cellulosic chains on elong ational and shear viscosity is greater at low deformation rates. Low DP sol utions behave more like viscous fluids and the increase of the chain length brings about an increase of the elastic component. Orientation induced by the convergence flow is enhanced by the higher DP cellulosic chains. (C) 20 00 John Wiley & Sons, Inc.