Title : Valorization of alginic acid from sargassum for bioplastics
Abstract:
The growing demand for sustainable alternatives to petroleum-derived plastics has spurred interest in biopolymers, such as sodium alginate, derived from the brown algae known as Sargassum. This study examines two complementary strategies for vaporizing alginates for bioplastic applications by investigating the effects of plasticizers on alginate-based materials and evaluating the impact of methylation and acetylation on the properties of alginic acid. The effect of a glycerol silicate (GS) plasticizer on the mechanical, thermal, and hydrophobic properties of sodium alginate (NaAlg) and calcium alginate (CaAlg) films was evaluated. NaAlg and CaAlg films showed poor mechanical properties, and plasticizing with GS up to 25 wt%. CaAlg achieved the highest tensile strength, while NaAlg's elongation at break increased by about 10-fold. TGA showed reduced thermal stability for NaAlg but maintained stability for CaAlg. Hydrophobicity decreased for NaAlg and initially increased for CaAlg before becoming hydrophilic at higher GS levels. GS effectively enhances alginate films for sustainable bioplastics. Functionalization of alginic acid (from sodium alginate) through methyl esterification followed by acetylation, resulted in novel methyl alginate acetate, resulting in enhanced hydrophobicity and improved film-forming properties for packaging applications. These modifications extend the versatility of alginate-based materials and align with the sustainability goals of reducing global reliance on petroleum-based plastics.
