Innovative Biodegradable PVA–Starch Films Reinforced With Clay And Lime: Advancing Sustainable Packaging For Climate Resilience

Abstract

Heightened global apprehension over the environmental pollution of conventional plastics and its undesirable effects on climate has accelerated research interest in biodegradable polymeric materials. In this study, bioplastic films derived from starch and polyvinyl alcohol (PVA) were reinforced with varying concentrations of calcium oxide (CaO) commonly known as lime and bentonite clay aiming to improve structural and functional properties. Bioplastic films were systemically evaluated with respect to mechanical strength, thermal behavior, moisture retention, water absorption and biodegradable behavior. Among all the formations the sample containing elevated amount of both CaO and bentonite (S7) exhibited the most favorable properties profile, attaining the tensile strength of 18.7 MPa and elongation at break of 93.19%, with thermal degradation commenced above 300 °C, reflecting noticeable thermal resistance. In contrast the high bentonite–low CaO (S47) sample demonstrated the lowest water absorption (21.8%) and moisture retention (8.21%), indicating strong barrier performance. In soil burial tests, S7 film demonstrated maximum degradation after 60 days, indicating great biodegradability. Scanning Electron Microscopy (SEM) revealed clear morphological variation among the selected samples, FTIR analysis confirmed the interaction of fillers and the PVA-starch films, while Principal Component Analysis (PCA) effectively distinguished performance relationships among formulations. K-means clustering further classified S7 with in high performance group. This integrated analytical approach underscores the prospective capabilities of dual-filler reinforcement in enhancing properties of biofilms. The results provide valuable insights into designing sustainable packaging materials as alternatives to petroleum-based plastics.