Sustainable Upcycling of Waste Banknotes into High-Performance Cellulose Acetate: Properties, Characterization and Environmental Implications

This study investigates the feasibility of recycling waste banknotes into cellulose acetate (CA), aiming to provide a sustainable solution for managing this challenging waste stream. The research goals were to successfully convert banknote cellulose into CA and compare its properties with commercial cellulose acetate (CCA). Methodologies employed include acetylation of waste banknote cellulose, followed by comprehensive characterization using Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and rheological measurements. Additionally, the study assessed the degree of substitution, polymerization, heavy metal content, tensile strength, moisture absorption, and thermal stability of the produced CA. Key findings demonstrate successful acetylation of banknote cellulose, confirmed by FTIR analysis. The laboratory-produced cellulose acetate (LCA) exhibited comparable tensile strength (2.02 MPa) and porosity (10.3%) to CCA. Notably, LCA showed significantly lower elongation (32% vs. 37% for CCA) and reduced moisture absorption, indicating superior ductility and dimensional stability. Thermal analysis revealed typical CA decomposition behavior, with onset around 300 °C. Rheological studies showed favorable non-Newtonian, shear-thinning behavior, suggesting good processability. These results demonstrate that waste banknotes can be effectively converted into CA with properties comparable or superior to commercial products, offering a promising avenue for value-added recycling of this waste stream and contributing to circular economy principles.