Konjac glucomannan/hydrophilic isocyanate aerogel modified by montmorillonite and aluminum hydroxide with increased mechanical strength and excellent flame retardancy

The development of flame-retardant thermal insulation aerogels with mechanical strength is of great significance to solve the fire problem of high-rise buildings. Montmorillonite (MMT) and aluminum hydroxide (ATH) have attracted much attention in polymer flame-retardant modification due to their safety, non-toxicity, and flame retardancy. In this work, the effects of two fillers on the mechanical properties, thermal insulation properties, thermal stability, and flame retardancy of konjac glucomannan/hydrophilic isocyanate aerogels were compared. The as-prepared aerogels exhibited low density (0.0514 ± 0.0031–0.1068 ± 0.0042 g/cm3), low thermal conductivity (0.0454 ± 0.00015 W/mK ∼ 0.05925 ± 0.002098 W/mK), high porosity (92.44 ± 1.02% ∼ 94.53 ± 0.98%). Compared with neat aerogel, the compressive modulus of aerogel with MMT improved from 0.1860 MPa to 1.9840 MPa. The peak heat release rate (PHRR) of the aerogels with MMT and ATH reduced by 58.6%, and 86.3%, respectively. Adding MMT has a better effect on improving mechanical properties, while adding ATH has a better flame-retardant effect. This study has certain reference value for developing eco-friendly bio-based aerogel building insulation materials with high fire safety.