Biopolymers

The rheological behaviors of concentrated cellulose solutions including cellulose/ionic liquid solutions varied with the dissolving process, cellulose/ionic liquid/DMSO solutions, cellulose/protein/ionic liquid solutions have been studied to predict the microphase morphology of different systems. The viscosity, relaxation time and sol-gel temperature of cellulose/ionic liquid solution shift to low value with the effective shearing action of kneading. This indicates significant differences occurring in the structuralization of solutions prepared by different dissolving process. The SEM images of films regenerated from kneading solution exhibited a dense and homogeneous morphology while films prepared by static-state dissolving process were loose with coarse aggregation, which is consist with the deduce from the rheological results. From the viscoelastic properties of cellulose solutions with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and dimthylsulfoxide (DMSO) as solvents, the non-monotonous decrease of viscosity with DMSO content was observed. When the content of DMSO in [BMIM]Cl/DMSO is lower than 5 wt% in [BMIM]Cl/DMSO, the viscosity and gelation temperature (Tgel) decreased with the increase of DMSO. However, the values of viscosity and Tgel showed nonlinear change with the further increase of DMSO. It could be understood that DMSO acted as the diluent when the content of DMSO is below 5 wt%. The local micro-aggregation or micro-phase separation of cellulose could be happened when the content of DMSO further increased due to the weak action between cellulose and DMSO. The viscosity of cellulose/protein/ionic liquid solution shows different correlations with blend ratio and shear rate, which is related to multiphase structure of cellulose blend systems.