Bio-Based Foams from Agricultural Waste: Optimizing Corn Starch-Corn Husk Composites with Xanthan Gum for Cushioning Applications

With the escalating environmental impact of petrochemical-based packaging, the development of biodegradable alternatives from agricultural waste has become imperative. This study describes the fabrication and optimization of a sustainable, bio-based cushioning material derived from a corn starch foam matrix and corn husk fibers via compression molding. The investigation of starch ratios revealed that 100% normal corn starch (NCS) provided superior expansion and structural integrity compared to waxy starch, which exhibited significant cell wall collapse under SEM analysis. To enhance formability, xanthan gum (XG) was incorporated as a stabilizer; a 1.0% (w/w) concentration was found to be the morphological inflection point, yielding a refined closed-cell structure and a bulk density of 0.43 g/cm3. The stabilized matrix was reinforced with 2.0% to 6.0% (w/w) corn husk fibers pre-treated with tetraethoxy silane (TEOS) to improve interfacial adhesion. The addition of 6.0% fibers significantly augmented the material's energy absorption capacity, achieving a peak impact strength of 1.87±0.50 kJ/m2 and a compressive strength of 0.56 N/mm2. These results demonstrate that the optimized agricultural waste-derived composite effectively surpasses the load-bearing capabilities of traditional commercial foams, offering a viable, eco-friendly solution for high-load protective packaging.