Efficient recovery of the dyed cotton–polyester fabric: cellulose nanocrystal extraction and its application in composite films

Herein, cotton fiber and polyester fiber were separated from their blended fabric by a dilute acid pretreatment combined mechanical grinding process with a total recovery rate of 92.1 %. The recovered cotton fiber was bleached and used to extract cellulose nanocrystals (CNCs). Compared with those extracted from the never-used cotton fibers, the resultant CNCs are lower in aspect ratio, higher in aqueous transparency and better in dispersion stability. Furthermore, the as-prepared CNCs, together with silica nanoparticles, were employed as the reinforcements to fabricate films with methylcellulose. The addition of the nanofillers endowed the pure methylcellulose films with a 200% improvement in tensile strength while slightly affected the transparency of the films. High-efficient recovering of dyed natural/synthetic fiber blended textiles, high-quality CNC extraction, and high-performance composite film fabrication achieved in this work is conducive to the utilization of waste resources and the saving of primary resources. Graphic abstract