Reinforcement effects of different types of chitin nanofibers on cellulose/chitin nanocomposite filaments

Recently, there has been a significant global focus on the development of fully biobased, strong, and tough filaments. This paper presents a deep investigation into the reinforcing effect of chitin nanofibers (ChNFs) on the fabrication of robust cellulose nanofiber (CNF)-ChNF composite filaments. Three types of ChNFs were produced using distinct. Methods aqueous counter-collision (ChACC), acid hydrolysis (ChAH), and TEMPO-oxidization (ChTEMPO). Subsequently, these ChNFs were blended with CNFs derived from hardwood bleached-kraft pulp to create the nanocomposites. The CNFs underwent TEMPO-oxidization and aqueous counter-collision (ACC) treatment. The composite filaments were fabricated via wet spinning, followed by coagulation in a CaCl₂ solution bath. A comparative analysis was conducted among all composites comprising various ChNFs and CNFs, examining their morphological, thermal, optical, and mechanical properties. Among them, the CNF-ChACC filament displayed the highest UV protection, while the CNF-ChAH filament demonstrated the highest tensile strength (614 MPa) and elongation-at-break, surpassing pure CNF filaments by 31.5% and 47%, respectively. It is anticipated that this study will contribute to a deeper understanding of the production of strong biobased filaments for advanced applications.