A synergistic self-assembly strategy to fabricate thermally stable OPAN/PI composite aerogels for particulate matter removal

Abstract

The development of low-cost nanofiber aerogels with good mechanical and thermal properties is essential for practical applications in the fields of heat insulation, air filtration, etc. In this study, we prepared pre-oxidized polyacrylonitrile/polyimide (OPAN/PI) composite aerogels with good thermal stability and mechanical properties by a simple synergistic strategy. A small amount of PI was used as a binder to successfully construct the porous structure of the nanofiber network. The obtained aerogel material exhibited excellent resilience, which can withstand 500 cycles of compression. In addition, the samples had an extremely low thermal conductivity (≈27 mW (m k)⁻¹) and a high limiting oxygen index (LOI > 36), showing improved thermal stability. It also had a high filtration efficiency for particulate matter while maintaining a low pressure drop owing to the hierarchical porous structure, and the filtration efficiency for PM2.5 can reach 99.46%. More importantly, it displayed a high dust-holding capacity, reaching approximately 90 g m⁻² due to the high porosity and pore volume. In short, the material shows great application potential in the field of high temperature filtration, heat insulation and flame retardants.