Physicochemical, mechanical, and degradation studies of short corn husk fiber-starch tapioca-agar film biocomposite foams

This study presents the synthesis and performance evaluation of a rigid biodegradable biofoam derived from short corn husk fiber, tapioca starch, and agar powder as an eco-friendly alternative to expanded polystyrene packaging. Spectroscopic and structural analyses confirmed effective hydrogen bonding and chemical compatibility among cellulose, lignin, starch polymers, and agar polysaccharides, contributing to a high crystalline fraction of 75.52%. Thermal testing demonstrated excellent endurance, with initial thermal decomposition occurring at 463.67 °C and leaving a residual mass of 17.79%. Morphological evaluation revealed a porous yet cohesive internal structure with a textured surface profile. Tensile measurements established robust mechanical stiffness, yielding an ultimate tensile strength of 1.852 MPa, a yield strength of 1.816 MPa, and an elongation at break of 2.88%. Functional performance testing showed a water absorption resistance of 22.18% and an initial soil burial weight loss of 9.50% over 20 days. Linear extrapolation suggests a full theoretical degradation period of ~200 days (~6.7 months), fully complying with the Indonesian National Standard (SNI) benchmark for biodegradable packaging (6–9 months). Overall, these findings highlight the viability of utilizing agricultural corn residue in multi-component biopolymer matrices to fabricate sustainable rigid food containers.