Flame Retardancy Konjac Glucomannan Based Aerogel Enhanced by Aluminum Hydroxide Coated Hollow Glass Microspheres

The development of green and environmentally friendly flame retardant materials has attracted widespread attention in modern architecture. In this work, a kind of novel aerogel was prepared by the incorporation of Al(OH) 3 coated hollow glass microspheres (HGM) into konjac glucomannan (KGM) matrix and then cross-linking by CaCl 2 (abbreviated as KGM-HGM-Al(OH) 3 ). The prepared KGM-HGM-Al(OH) 3 aerogel exhibits a porous structure with a high porosity of 93.93%, endowing it with excellent thermal insulation performance. In addition, it exhibits excellent thermal stability, and the mass loss of KGM-HGM-Al(OH) 3 aerogels is 37.6% at 800°C. More importantly, the aerogel shows excellent flame retardancy, with the peak heat release rate (pHRR) and total heat release (THR) of 21.43 kW m −2 and 1.895 kJ m −2 , respectively. Furthermore, the limiting oxygen index (LOI) is 54.5%; this superior performance is primarily attributed to the synergistic effect of HGM-Al(OH) 3 . The hollow structure of the hollow glass microspheres effectively delays the internal heat transfer, Al(OH) 3 decomposes endothermically at high temperatures to form an Al 2 O 3 barrier layer, while releasing water vapor to dilute combustible gas, so that the KGM-HGM-Al(OH) 3 aerogel has excellent flame retardancy. The aerogel material has the advantages of low cost and a simple preparation method, and has extensive application value in the fields of building fire resistance and battery fire resistance.