Sustainable valorization of mandarin peel waste into multifunctional cellulose/pectin/PVA films with superior mechanical and UV-blocking performance

Abstract

Biodegradable polymers offer a promising solution to global plastic pollution. However, commercial options such as poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) often rely on petroleum-based feedstocks or costly microbial production. Lignocellulosic biomass presents a sustainable alternative, yet a substantial amount is discarded, and its utilization remains limited. In this study, we present a more sustainable and cost-effective approach to fabricating biodegradable plastic films from mandarin (Citrus reticulata Blanco) peel waste. Using a simple, one-step process with aqueous sodium carbonate as a mild pretreatment reagent, we partially hydrolyze the mandarin peel structure while simultaneously blending it with poly(vinyl alcohol) (PVA). To further enhance functionality, additional post-treatments including ultrasonication and washing are employed. The optimized films demonstrate excellent tensile strength (∼60 MPa), near-complete UV-blocking (∼100%), and strong antioxidant activity (∼54% radical scavenging). Furthermore, the films exhibit outstanding oxygen barrier properties and enhanced water vapor barrier properties. Finally, biodegradation under simulated river water and soil conditions, as well as soil ecotoxicity assessments, confirms the products' minimal environmental impact in various end-of-life scenarios. These findings highlight the potential of the developed material for packaging and agricultural mulch applications, addressing both plastic waste pollution and biomass valorization.