Nanofibers reinforced silica aerogel composites having flexibility and ultra-low thermal conductivity

For the sake of enhancing the performance of flexible silica aerogel in practical applications, flexible SiO2/SnO2 nanofibers (SSNF) reinforced flexible silica aerogel composites (abbreviated as SiO2-SSNF) were successfully prepared. Firstly, the SiO2/SnO2 nanofibers with fine diameter (similar to 320 nm) and excellent flexibility were prepared by electrospinning technology. Then the aerogel composites were synthesized by adding the flexible SSNF to the silica solution and through the sol-gel method and ethanol supercritical drying technology. The effects of different content of the nanofibers on thermal conductivity and Yong's modulus of SiO2-SSNF aerogel composites were investigated. The SiO2/SnO2 nanofibers were randomly dispersed in the flexible silica aerogel and the great integrity of the material result in smaller linear shrinkage, better thermal protection, and mechanical properties compared with those pure SiO2 aerogels. The final SiO2-SSNF aerogel composites possess excellent thermal conductivity (0.025-0.029 W/(m.K)) and higher Yong's modulus (70 kPa), which was twice than that of the pure silica aerogel. This prepared SiO2-SSNF aerogel composites can be better used in thermal insulation due to its excellent flexible and thermal insulation property.