Muscular Kevlar aerogel fibers appealing to thermal insulation with a symbiotic core-sheath structure

High-performance aerogels offer a broad application prospect owing to their various features such as high specific surface area and attractive thermal insulation. However, their porous structure confers weak mechanical properties to aerogels. The strategy of coaxial wet-spinning was implemented to strengthen Kevlar aerogel fibers and improve their usability. Prepared Kevlar aerogel fibers have a symbiotic core–sheath structure, with a blurred division between core and sheath. In addition, the breaking stress of Kevlar aerogel fibers can reach 2.6 MPa, which is four times that of the core, presenting a significant improvement in tensile strength compared to those in previous studies. Moreover, Kevlar aerogel fibers exhibit superior thermal stability, which is inherited from Kevlar fibers, and decomposed after 480 °C. Moreover, their high porosity and high specific area (∼400.5 m2·g−1) endow them with outstanding thermal insulation properties. When fabrics woven from these fibers are exposed to a 300 °C hot plate, the temperature on the surface can be 110 °C lower, resulting in a significant temperature gradient of 83 °C·mm−1. In total, the resultant Kevlar aerogel fibers with a symbiotic core–sheath structure are used as fillers for protective clothing or fire insulation blankets and similar items.