Semi-interpenetrating networks of ANF/SiO2 composite aerogel with lightweight, compressible, and excellent flame retardancy properties

To design ultralight nanocomposite aerogels with good compatibility of different components, excellent thermostability, flame retardancy and strength is an urgent issue to be addressed. In this work, we fabricated a lightweight, compressible aramid nanofiber/silicon dioxide (ANF/SiO₂) composite aerogel by sol-gel method. The homogeneous SiO₂ knots were formed in-situ among the nanofibers resulting a semi-interpenetrating network structure. Due to the supporting effect of the ANF on the overall skeleton and the inhibiting effect of SiO₂ the compression properties of the ANF/SiO₂ aerogels were significantly improved. In addition, the aerogel shows low thermal conductivity, excellent thermal stability and flame retardancy meanwhile advanced self-extinguishing properties even after two minutes combustion. The design does not rely on any toxic or corrosive substances and provides a new insight into the preparation of composite aerogels with green, compressibility, thermal insulation and excellent flame retardancy.