Sargassum-Derived Bioplastic for Sustainable Packaging: Evaluation of Mechanical, Thermal, and Barrier Properties

Plastic pollution remains a critical environmental issue due to the persistence of petroleum-based plastics in natural ecosystems. This study evaluates Sargassum seaweed, an abundant coastal biomass in Malaysia, as a renewable feedstock for biodegradable bioplastic production. To overcome the inherent limitations of alginate-based bioplastics, glycerol 12.6% (w/w, relative to polymer mass) has been incorporated as a plasticizer, with calcium chloride (2% w/v) as a cross-linking agent. Bioplastic films were produced via alginate extraction, film casting, and drying, and characterized through tensile testing, differential scanning calorimetry (DSC), water absorption, grease absorption, and biodegradability analyses. The modified Sargassum-based bioplastics exhibited enhanced tensile strength (maximum force up to 6.67 N), improved elongation at break (up to 31.33%), and increased thermal stability, with a melting temperature of 160°C and degradation onset at 190°C. Swelling, biodegradation, and oil uptake behaviors were governed by the interplay between hydrophilic diffusion and calcium-mediated cross-link stabilization. Complete biodegradation was observed within 30 days in soil. These findings demonstrate that formulation optimization allows Sargassum-derived bioplastics to achieve balanced mechanical performance, barrier properties, and environmental degradability. This will enhance their potential for sustainable single-use packaging applications.