Cellulose fibres from regional plants like miscanthus have gained a lot attention as a replacement of synthetic fibres due to their eco-friendly nature, abundant local availability, low cost, reducing "food versus fuel" competition and their application in bio-based composites. Typical ways to obtain the natural fibres in practice are mainly refining and/or cooking processes. In our study, extrusion technology was used for fibrillating the fibres for preparing the reinforcement of cellulose-based composites.
Using a twin-screw extruder, miscanthus was extruded in different swelling media. The extrudates were purified and analysed for fibre morphology and chemical composition. It could be shown that the swelling media significantly influences the fibrillation process, leading to different fibre morphology. In a second extrusion step, selected extrusion-fibrillated fibre materials were compounded with cellulose-based matrices such as cellulose acetate (CA) and cellulose acetate butyrate (CAB) to produce injection-mouldable cellulose composites. The mechanical properties of the compounds were compared to the unmodified grades and to compounds made with the drop-in biopolymers bio-PP und bio-PE as matrices. The rheological and morphological properties were characterized as well. It is shown that the mechanical properties of cellulose-fibre reinforced CA prepared this way are comparable to those of glass fibre-reinforced polypropylene (GF-PP) with similar fibre content (20 wt. %).