Preparation of composite aerogels with excellent flame retardant and thermal insulation properties based on modified hollow glass microspheres

The development of high-quality thermal insulation material with exceptional flame-retardant qualities is crucial to reducing energy consumption in buildings and minimizing the risk of fire. Herein, we report the preparation of organic-inorganic composite aerogel by coating Mg/Al-LDH and phytic acid onto the exterior of hollow glass microspheres to obtain PLHGM, mixing PLHGM with the solution of sodium alginate and carboxymethyl cellulose to prepare the SA/CMC-PLHGM aerogel. The synthetic aerogel has exceptional thermal insulation with a thermal conductivity of 0.046 Wm⁻¹K⁻¹. Meanwhile, SA/CMC-PLHGM aerogel has a high limiting oxygen index value is greater than 90%, reaching the UL-94 test V-0 rating. In the cone calorimetry test, the peak heat release rate (pHRR) is 32.97 kW/m², a 55.19% reduction from the sodium alginate/carboxymethyl cellulose aerogel (SA/CMC aerogel), and the SA/CMC-PLHGM aerogel has lower CO and CO₂ production rates compared to the SA/CMC aerogel. The SA/CMC-PLHGM aerogel has properties of lightweight, porous, thermally stable, flame-retardant properties, and superior thermal insulating properties which provide a novel strategy for the practical use of aerogel in the field of modern building construction thermal insulation materials with flame-retardant properties.