A waste hemp‐based biomass carbon aerogel with high fire‐resistance

Abstract To enhance the efficient utilization of waste hemp rods, a kind of three‐dimensional (3D), mesh‐like lamellar structured hemp‐based biomass carbon aerogel (CA) was developed by freeze‐drying and subsequent high‐temperature carbonization method. The microstructure, flame resistance, thermal stability, and thermal conductivity of CA were investigated using several analytical techniques, including scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), simulated combustion tests, and thermogravimetric analysis (TG). Optimum formulation yielded at an alkali treatment concentration of 20% and a carbonization temperature of 700°C, CA with a 3D network of reticulated lamellae was obtained. CA exhibited minimal values for thermal conductivity (0.06 W/m K) and thermal diffusion coefficient (0.41 mm 2 /s), which are indicative of superior insulative properties. Moreover, the material demonstrated remarkable thermal endurance and flame resistance, achieving a char yield of 70.03% when subjected to a temperature of 700°C in an oxidative environment.