Process-dependent nanostructures of regenerated cellulose and bio-based composite fibers

Reshaping is an important step to use cellulosic materials for industrial applications and spinning is one of the major processes for the cellulose industries. In this research project, the nanostructural details of regenerated cellulose fibers and their composites are studied to understand the relationship between structural parameters and mechanical properties. Pure cellulose fibers samples were prepared by dry-jet wet spinning (Lyocell technology) and by modified viscose processes. Bio-based multicomponent composite fibers were prepared by a recently developed spinning system using an ionic liquid ([DBNH]OAc, Ioncell technology) with additive biopolymers like chitosan, lignin and keratin. Small angle neutron and X-ray scattering was employed to shed light on the hierarchical structure of multicomponent system of these fibers. The obtained information is essential to improve the mechanical properties of cellulose fibers and to develop novel bio-based composite materials. The recent findings of this project include the identification of divergent nanostructures of the cellulose elementary fibrils which are connected to the spinning processes. Further, a co-orientation mechanism of additive biopolymers during the spinning process was found in the cellulose composite fibers.