Enhanced thermal, antimicrobial, water-resistance, and tensile properties of PVA packaging films reinforced with iron oxide nanofillers synthesized from spinach biomass extracts

This study demonstrated the successful valorization of agro-waste by utilizing spinach biomass extract for the green synthesis of iron oxide nanoparticles (IONPs). The characterization confirmed the formation of spherical, crystalline nanoparticles with an average size of 102 nm, a crystallinity index of 70.4%, and high thermal stability, with a major degradation peak at 230°C. When incorporated into polyvinyl alcohol (PVA) films, the IONPs imparted multifunctional properties. A 3 wt% IONP loading was identified as optimal, resulting in a composite film with a 32.89 MPa Young’s modulus, a 16.8% reduction in moisture content compared to pure PVA, and significant antimicrobial activity. These properties position the spinach-derived IONP/PVA composite as a sustainable and effective material for active food packaging, directly addressing waste valorization and the need for high-performance, biodegradable polymers.