Ultra‐strong and biodegradable nanocomposite fibers of poly(butylene adipate‐co‐terephthalate)/cellulose nanocrystal prepared by dry‐jet wet spinning

Abstract Fiber‐based products constitute a significant portion of plastic waste and cause environmental damage. In particular, discarded sanitary masks and fishing gear disintegrate into microfiber plastics, posing a significant threat to human health and ecosystems. In this study, we developed robust biodegradable nanocomposite fibers of poly(butylene adipate‐co‐terephthalate) (PBAT)/cellulose nanocrystals (CNCs) (1 and 2 wt%) through dry‐jet wet spinning, by using dimethyl sulfoxide (DMSO) as a common solvent. The control PBAT fibers exhibit remarkable mechanical performance with tensile strength and toughness of 160.0 MPa and 43.0 MJ m⁻³, respectively. CNC addition has a toughening effect with slightly reduced strength but enhanced toughness (148.8 MPa and 69.0 MJ m⁻³, respectively, for 2 wt% CNC); their mechanical performances are superior to those of previously reported PBAT‐based materials. The remarkable performance of the fibers is attributed to a highly oriented structure with a total draw ratio of 15 after post‐hot drawing. The control and nanocomposite fibers exhibit spot‐like patterns in 2D wide‐angle x‐ray diffraction patterns with Herman's orientation factor of 0.54–0.58. The theoretical Hansen solubility parameter confirmed the poor chemical affinity between the PBAT and CNC. Nonetheless, the rheological characterization revealed that well‐dispersed CNCs with DMSO produced a physical network in the PBAT matrix, resulting in the toughening effect. Such robust nanocomposite fibers consisting of fully biodegradable components are promising alternatives to nondegradable nylon and polyester fibers. Highlights Robust biodegradable nanocomposite fibers of PBAT and CNC are prepared. Nanocomposite fibers are dry‐jet wet spun using DMSO as a common solvent. PBAT fibers exhibit strength and toughness of 160.0 MPa and 43.0 MJ m⁻³. 2 wt% CNC toughens the PBAT fibers with an enhanced toughness of 69.0 MJ m⁻³. Rheological results confirm the toughening effect of well‐dispersed CNC in PBAT.