Pure Chitosan-Based Fibers Manufactured by a Wet Spinning Lab-Scale Process Using Ionic Liquids

Ionic liquids offer alternative methods for the sustainable processing of natural biopolymers like chitosan. The ionic liquid 1-butyl-3-methylimidazolium acetate (BmimOAc) was successfully used for manufacturing of pure chitosan-based monofilaments by a wet spinning process at lab-scale. Commercial chitosan with 90% deacetylation degree was used for the preparation of spinning dopes with solids content of 4-8 wt.%. Rheology tests were carried out for the characterization of the viscometric properties. BmimOAc was used as a solvent and deionized water as coagulation and washing medium. Optical (scanning electron microscope (SEM), light microscope) and textile physical tests were used for the evaluation of the morphological and mechanical characteristics. The manufactured chitosan monofilaments a homogeneous structure with a diameter of ~150 μm and ~30 tex yarn count. The mechanical tests show tensile strengths of 8 cN/tex at Young's modulus up to 4.5 GPa. This work represents a principal study for the manufacturing of pure chitosan fibers from ionic liquids and provides basic knowledge for the development of a wet spinning process.