Ultrahigh-Temperature Insulating and Fire-Resistant Aerogels from Cationic Amylopectin and Clay via a Facile Route

Emerging environmentally friendly materials with ultrahigh-temperature thermal insulation, high fire resistance, and cost efficiency are in high demand in the fields of aerospace and high-rise building insulation materials. Herein, we tackle these dilemmas by fabricating a sustainable, eco-friendly, robust biobased aerogel through cross-linking a very small proportion of biobased cationic amylopectin derivatives with montmorillonite clay to form strong 3D networks within 20 s via electrostatic force and hydrogen bonding. The resultant aerogels with special microstructure of "brick-mortar-bridges" have low density (25 mg/cm3), practical mechanical strengths (10–40 kNm/kg), low thermal conductivity, high-temperature insulation, and heat resistance up to 1400 °C. Remarkably, this aerogel of 10 mm thick prevents the temperature of the nonexposed side from increasing above 250 °C after being heated by a 1400 °C flame for 30 min. This aerogel resists a butane blowlamp flame without disintegrating and shows high torch-fire endurance with limiting oxygen indexes above 60%. The excellent high-temperature thermal insulation and fire resistance of the MMT/CAP aerogels can effectively protect the wall from collapse and allow sufficient time for evacuation of personnel. The specific design of cationic amylopectin binding to anionic clay by noncovalent forces is promising for fabricating thermal insulating aerogels with great ultrahigh-temperature/fire resistance and cost efficiency.