Fire‐Retardant and Thermal‐Insulating Cellulose Nanofibril Aerogel Modified by In Situ Supramolecular Assembly of Melamine and Phytic Acid

The widespread utilization of cellulose nanofibril (CNF) has been significantly hindered by its inherent flammability. To explore the potential of using CNF aerogel as sustainable material with good fire‐retardant and thermal‐insulating properties, CNF aerogel is modified by in situ supramolecular assembly of melamine (MEL) and phytic acid (PA). This strategy addresses CNF's flammability and avoids the environment issues associated with the incorporation of traditional fire‐retardant. The modified aerogel exhibits highly porous honeycomb structure with low density and good mechanical properties. After modification with MEL–PA, the aerogel exhibits highly improved shape integrity during burning, higher thermal stability, and favorable combustion behavior for fire retardancy. The heat transfer of the modified aerogel is well hindered, which demonstrated effective thermal insulation performance. In view of the excellent thermal and fire‐retardant properties, the MEL–PA/CNF composite aerogel can be a potential fire‐retardant and thermal‐insulating material for applications such as clothing, building, and electronic devices.