A hydrophobic and flexible thermal insulation composite prepared by in situ formation of SiO2 aerogel in aramid fiber felt and introduction of SiC

Silicon dioxide aerogel, with its low density and porous structure, is a promising material for thermal insulation. In this paper, SiO₂ aerogel/silicon carbide/aramid fiber felt (SiO₂/SiC/AFF) composites were successfully prepared by using low-cost aramid fiber mats as reinforcement and inhibiting the heat radiation transfer by introducing silicon carbide. The results showed that SiO₂/SiC/AFF was characterized by light weight, flexibility, low thermal conductivity (0.019 W·(m·K) ^-1), and good hydrophobicity (123.19°). The tensile strength and elongation at break of the composites were 1.04 MPa and 74.25 %, respectively. More importantly, due to the large amount of SiO₂ aerogel and SiC particles attached to the felt. Therefore, the thermal insulation as well as flame retardant properties of the composites were effectively improved compared with those of the aramid fiber felts. In summary, the composites have potential applications in the field of thermal insulation.