Wood fiber reinforced oxidized starch-based composite foam: biobased, flame retardant and hydrophobic

In this study, a novel foaming method combining chemical modifications, mechanical stirring and solvent exchange was proposed for successful preparation of novel starch-based foams with high biomass content based on oxidized starch (OC). The method overcomes the limitations of traditional foaming means in the preparation of large-volume starch-based foams and provides a new path for their sustainable application as building insulation materials. By introducing birch wood fiber (WF), the biobased flame retardant (PC) and methyltrimethoxysilane solution (MTMS), the mechanical properties, flame retardancy and hydrophobicity of the foam have been significantly improved. Fourier transform infrared spectroscopy (FTIR) was applied to confirm the cross-linking reaction between the materials, and scanning electron microscopy (SEM) revealed that the foams and composite foams had homogeneous cellular structures. The samples produced through optimized procedures were determined to have excellent overall properties, including high bulk modulus, good thermal stability, self-extinguishing characteristics (no melt droplets, UL-94 HBF grade), low pulverization ratio and thermal conductivity, demonstrating their potential for replacing traditional polyurethane (PU) and polystyrene (EPS) foams.