The use of Sargassum for the development of biodegradable bioplastic composite

Introduction: This study explores the feasibility of utilizing invasive pelagic Caribbean Sargassum fluitans and Sargassum natans as renewable feedstocks for the development of biodegradable bioplastic composites. Many previous studies focused on single-polymer alginate films or isolated mechanical properties; however, this research aimed to develop a mixed polymer, mixed filler alginate biocomposite designed to enhance multiple physico-chemical properties. Materials and methods: Alginate extracted from both Sargassum species was incorporated with carboxymethyl cellulose (CMC), microcrystalline cellulose (MCC), starch, and sorbitol to produce biocomposite samples at varying combination ratios. The effects of composition on tensile strength, water vapour transmission rate (WVTR), water solubility, soil biodegradation, and thermal degradation were evaluated. Results: The biocomposite sample with a ratio of 1:1.5:0.25:0.25:0.05 Alginate:CMC:Sorbitol:MCC:Starch resulted in the best overall performance with a tensile strength of 220.5 ± 0.5 kPa, WVTR of 27.74 ± 0.12 g/m 2 ∙h, soil biodegradation of 50.94 ± 4.18% after 6 days, water solubility of 55.27 ± 28.6%, and thermal degradation commencing at 280 °C. Conclusions: The findings demonstrate the potential for converting problematic Sargassum influx affecting the Caribbean coastlines to environmentally sustainable single-use bioplastic, supporting both marine waste mitigation and circular bioeconomy initiatives in Jamaica and the wider Caribbean region.