Fabrication of sustainable sodium alginate-based building thermal insulation composite aerogel with robust...

The construction of building insulation materials with high fire safety and sustainable development has become a hot research topic and urgent need in the field of architecture. However, traditional building insulation materials have the problems of flammability, inability to actively fire warning and lack of sustainable materials. Herein, polyvinyl alcohol/sodium alginate/Ag₂Se (PSA) composite aerogels exhibiting flame retardancy, fire warning capabilities, and self-healing properties were synthesized using a double cross-linking network and a freeze-thaw cycle strategy. The synergistic effect of boric acid and Ag₂Se nanoparticles significantly improved the flame retardancy of PSA aerogels. The peak heat release rate decreased by 18.2%, and the total heat release rate decreased by 41.1%. Utilizing a low thermal conductivity of less than 0.08 W·m^-1·K^-1, a stable temperature differential is established between the hot and cold ends. Through the thermoelectric effect of Ag₂Se, a fast self-powered fire alarm within 3 s after contacting the flame is realized. Both of them improved the fire safety of PSA aerogels. Based on the natural polysaccharide sodium alginate as the matrix, the dynamic borate ester bond reconstruction is triggered by water to achieve 2 min of rapid self-healing without losing the self-powered fire warning function, which has the sustainable advantages of environmental friendliness and high durability. PSA aerogel provides an intelligent and collaborative solution for building thermal insulation materials with high fire safety and sustainable development through reversible fire warning and robust self-healing performance, which significantly promotes its practical application in the construction field.