Construction of carrageenan-based foams with multilevel structures for efficient hazardous chemical absorption, super insulation and fire protection

The present study reports the successful fabrication of a carrageenan-based foam with multilevel structures for efficient hazardous chemical absorption, super insulation and fire protection. By cross-linking carrageenan with swollen vermiculite nanosheets via iron ions and combining with the ablative resistance of inorganic nanofibers, the foam achieves a unity of intrinsic flame retardancy, toughness, thermal insulation and fire resistance. The influence of the composition and structure on the properties of the foam is systematically investigated. Benefiting from the unique multilevel structure, the prepared carrageenan-based vermiculite-silica nanofiber (CA-VNS-SiO 2 ) composite foam exhibits a low thermal conductivity of 0.0377 W·m −1 ·K −1 , meets the UL-94 V-0 fire protection standard, and possesses an oxygen index of 69.5 %. Compared to pure carrageenan foam, it shows a significant reduction in total heat release by 84.1 %. Moreover, the foam demonstrates excellent hydrophobicity and adsorption capacity for various organic oil pollutants. These findings indicate that this study provides a green and cost-effective strategy for producing high-performance carrageenan-based foams with great potential in practical applications.