Metal-organic framework incorporated polybenzimidazole aerogel fibers with dual protections for thermal hazards and chemical warfare agents

Aerogel fibers possess the flexibility of fiber materials and the high porosity and low thermal conductivity of aerogel materials, which hold great promising for applications in thermal insulation and personal protection. However, the inferior mechanical performance and the lack of functionality have impeded the wider applications of these fascinating materials. Herein, we report a novel kind of MOF/polybenzimidazole composite aerogel fibers (CAFs) with both physical and chemical protection functions. The CAFs are fabricated by an oxidation induced sol–gel transition spinning method that utilized the transition of labile imidazole/Co2+ coordination bonds to stable imidazole/Co3+ coordination bonds upon oxidation. The incorporation of MOF has obviously improved the strength and ductility of CAFs due to the good interfacial interactions with matrix and increased crosslinking among polymer chains. The CAFs maintain the high thermal stability and flame retardancy of polybenzimidazole matrix, while the increased porosity and surface area with the addition of MOF have lowered the thermal conductivity and improved the thermal insulation performance of CAFs. The uniform porous skeleton also facilitates the access of chemical warfare agents (CWAs) to MOF inside the fiber. The catalytic experiments show that the CAFs have better degradation effect on CWAs than pure MOF powder, dense composite fiber, and MOF coated fiber. This work is expected to provide an efficient strategy for strong and multifunctional aerogel fibers.