Complete recycling and valorization of waste cotton-spandex blended fabrics into value-added UV-blocking cellulose/graphene films and transparent polyurethane film

Most of waste textiles are disposed by incineration and landfill, leading to huge waste of natural resources and seriously ecological disasters. Hence, complete recycling and valorization of waste textiles into value-added products via a relatively economical and green approach is important and meaningful. This work presented a method of highly utilizing waste cotton-spandex fabrics to prepare value-added UV-blocking cellulose/graphene films and transparent polyurethane (PU) film based on the solubility difference of cotton and spandex fibers in 1-allyl-3-methylimidazolium chloride (AmimCl). It was found that AmimCl can dissolve cotton fibers efficiently without destroying the spandex fibers and waste spandex fibers were separated successfully from cellulose solution. Subsequently, the cellulose/AmimCl solution was in-situ composited with graphene to prepare the cellulose/graphene composite films with good mechanical, thermal and UV-blocking properties. Particularly, the tensile strength of cellulose/graphene films can reach as high as 15.1 MPa. Moreover, the UV-blocking capacity of cellulose/graphene films was improved significantly by increasing the content of graphene. Thus, cellulose/graphene films displayed huge potentials to be employed in anti-ultraviolet packaging and wrapping fields. Additionally, the polyurethane (PU) film with good self-adhesion, high transparency and elasticity was also obtained by dissolving the recovered spandex fibers in N,N-Dimethylformamide (DMF). As a result, waste cotton-spandex fabrics were completely recycled and valorized into high-value added cellulose/graphene films and polyurethane film by a relatively facile, feasible and eco-friendly process.