Core-shell structured BN/SiO2 nanofiber membrane featuring with dual-effect thermal management and flame retardancy for extreme space thermal protection

Abstract

With the rapid progress of aerospace frontier engineering, the extreme space thermal environment has brought severe challenges to astronauts’ space suits, putting forward higher requirements for thermal protection materials. On this basis, a unique core-shell structured hexagonal boron nitride (h-BN)/silicon dioxide (SiO₂) nanofiber membrane (HS) was prepared using the coaxial electrospinning method, of which both the thermal insulation SiO₂ nanofiber cortex and the passive radiation cooling (PRC) h-BN nanofiber core make it a promising dual-effect thermal management material. Especially, when the amount of h-BN is 0.9 g, the resultant HS (HS_0.9) exhibits astonishing low thermal conductivity of 0.026 W m⁻¹ K⁻¹ and high reflectivity and emissivity of exceeding 90% over an extremely wide range. The expected dual-effect thermal management performance enables the HS to have an ideal cooling effect under both high sunlight intensity and strong light radiation. In addition, HS also shows excellent flame retardant performance arising from the excellent high-temperature stability of h-BN and SiO₂. What is more, the tensile strength of HS_0.9 was also significantly increased from 0.42 to 7.2 MPa by encapsulating polyimide through vacuum filtration. Therefore, the research results of this work provide innovative highlights for high-temperature protection in daily life and even extreme space environments.