Preparation of high-strength and degradable films from waste soft tissue by thermal “welding” using ionic liquid

Abstract

This paper presents a simplified one-step method for preparing high-strength and degradable films, significantly enhancing the reuse value of waste cellulose fibers. By precisely controlling water evaporation, we successfully achieved partial dissolution of viscose fiber in ionic liquid ([BMIM]Cl). This enabled the bonding of fiber surfaces, resulting in the formation of all-cellulose composite films through a straightforward thermal “welding” process. The film properties can be further improved by modifying the coagulation bath composition. We conducted a comprehensive study on the morphology, mechanical properties, and thermal properties of all-cellulose composite films regenerated from different coagulation baths. XRD analysis revealed the coexistence of cellulose crystal phases I and II in the films. These composite films exhibited excellent mechanical properties, with a tensile strength of 25 MPa and a breaking elongation of 32% for the film regenerated in PEG coagulation bath. Moreover, the films demonstrated good thermal stability, resistance to chemical reagents, and a high light transmission rate of 80%. In a soil landfill degradation experiment spanning 90 days, the films exhibited a degradation rate of 93.4%. These films hold significant potential for applications in the field of specialized packaging materials. Overall, our work provides a promising and environmentally friendly approach for the recycling of waste cellulosic materials.