Lightweight Ambient-Dried Biobased Aerogels with Superior Fire Safety and Mechanical Durability for Thermal Insulation

Abstract

Biobased aerogels have emerged as promising thermal-insulation materials, offering a sustainable solution to mitigate global energy consumption. However, achieving aerogels with high environmental adaptability that combine thermal resistance, reliable fire safety, structural and mechanical durability, and energy-efficient fabrication processes remains a significant challenge. Herein, a low-carbon thermal-insulation aerogel is developed by integrating a synergistic carbonization design with green ambient drying techniques. Unlike traditional complex freeze-drying or hazardous solvent exchange methods, the strategic combination of thermoresponsive gel fixation and mechanical-assisted air templates enables the transformation of water-based foamy hydrogels into porous aerogels via a green ambient drying process, in which gellan gum and melamine-formaldehyde resin serve as carbonizable interpenetrating matrices, while boric acid acts as a catalytic carbonization/hybridization agent and participates in molecular cross-linking. The as-developed aerogel exhibits an impressive ability to provide comprehensive protection in various environments, combining rapid self-extinguishment (LOI = 50%), low heat/smoke hazard (30 kW/m²/1.6 m²), excellent fire resistance (blocking 75.5% heat of 1300 °C flame), and structural/mechanical durability (93%) in harsh environments (e.g., hot water, strong acids/alkalis, various chemicals) when featuring lightweight (43 mg/cm³), surpassing previous biobased aerogels. This work provides a straightforward and integrated approach to create high-performance aerogels, showing great commercial potential for massive applications in sustainable energy-efficient buildings.