Proceedings of the 4th international Symposium "Materials from Renewable Resources" pages:S4-16-1-13
4th international Symposium "Materials from Renewable Resources" edition:4 location:Erfurt, Germany date:11-12 September 2003
Water soluble, chemically modified cellulose is of broad interest because of the long time availability, their environmental friendly degradability and their physiological harmlessness. Cellulosic derivatives are widely used as thickeners, binding agents, adhesives, swelling agents, protective colloids, emulsion and suspension stabilizers and filmforming agents, to name a few. Despite these broad fields of application there are still many open questions remaining between molecular structure and application profiles.
Especially the viscoelastic properties of cellulosic derivatives in aqueous solution have to be interpreted regarding their molecular structure. The industrial important thickening properties can be captured by the so called 0–M–c relationships. These relationships can be expanded to the non-Newtonian flow regime ( = f()) which is also possible for not molecular disperse solutions of cellulosic derivatives with associated and aggregated clusters of polymers.
During the last years, new investigation methods were established which utilize rheo-optical techniques to measure the flow birefringence and dichroism. These methods allow a determination of the orientation of polymer segments and polymer aggregates in a shear flow field, the detection of the 1st normal stress difference, as well as the detection of sol-gel transitions. The combination of rheo-optical and rheo-mechanical investigations enables new insights into the complex solution structure of cellulosic derivatives.