Synthesis of nanocellulose from banana plant stem to fabricate PVA based biodegradable nanocomposite films

The significance of using environmentally friendly, renewable, and sustainable materials has increased dramatically in recent years. Organic fillers such as fibre, starch, and nanocellulose from waste materials have the potential to make biodegradable composites to alleviate the growing issue of plastic waste. This study focuses on creating biodegradable PVA nanocomposite films, which could serve as a viable substitute for traditional non-biodegradable plastics, using a readily available supply of waste banana plants to synthesise crystalline nanocellulose, avoiding energy-intensive methods. Nanocellulose was synthesised from the banana plant stem through acid hydrolysis, after which biodegradable nanocomposite films were produced by incorporating the nanocellulose in polyvinyl alcohol using the solution casting method. FTIR analysis revealed the formation of cellulose and the removal of hemicellulose and lignin. Furthermore, XRD analysis showed prominent peaks signifying the presence of cellulose type I structure with a crystallinity index of 66.60%. SEM analysis showed uniformly distributed nanoparticles with diameters of 29.1 ± 4.72 nm within the PVA matrix which correlated to increased mechanical properties as observed in tensile tests where incorporation of 1 wt%, 2w% and 3 wt% nanocellulose within the matrix increased the tensile strength (2.31%, 21.79%, 48.01% respectively), yield strength (26.91%, 38.92%, 96.94% respectively) and elastic modulus (11.24%, 64.50%, 75.52% respectively) with a reduced elongation at break (from 195.87 ± 18.04% for PVA to 139.25 ± 10.43%, 116.9 ± 10.06% and 105.33 ± 2.01% respectively). Moreover, the addition of nanocellulose led to increased thermal stability, reduced weight loss in soil and water uptake of the nanocomposite films. Reduction of water uptake and soil degradation indicated the potential usage of the nanocomposites in damp conditions where PVA alone could not be used, while maintaining their biodegradable nature. These results indicate the possibility of the nanocomposite films being used as a biodegradable substitute for HDPE and LDPE.