Direct Production of Sorbitol-Plasticized Bioplastic Film from Gracilaria sp.

Abstract

Conventional bioplastic production from seaweed often relies on extraction processes that are costly, time-consuming, and yield limited product. This study presents a direct fabrication method using Gracilaria sp., a red seaweed rich in polysaccharides, to produce bioplastic films without the need for extraction. Sorbitol was incorporated as a plasticizer at concentrations of 0%–10% (w/w) to modify film characteristics. Thermal analysis revealed improved stability at moderate sorbitol levels (5%–7%), while excessive plasticizer slightly reduced thermal resistance. Mechanical testing showed that sorbitol increased film flexibility and elongation at break, though tensile strength and stiffness declined. Tear strength followed a non-linear trend, with improvement observed at higher sorbitol concentrations. Seal strength also increased, peaking at 7%, indicating stronger interfacial bonding between film layers. Biodegradation tests demonstrated accelerated decomposition with increased sorbitol content, achieving complete degradation within 30 days at 10% concentration. Color analysis showed increased brightness and reduced yellowing, enhancing the visual quality of the films. These results confirm that direct conversion of bioplastic is both feasible and effective. Sorbitol plays a key role in tuning film properties, offering a low-cost, scalable pathway to biodegradable materials suitable for environmentally friendly packaging applications.