Continuous and strong polyimide aerogel fibers enhanced by para-aramid nanofibers prepared via a "Reaction Spinning" for thermal insulation

Strong and flexible aerogel fibers and their textiles with low density are attractive candidates for high -efficiency thermal insulation. However, most of the previously reported aerogel monoliths and fibers suffered from weak mechanical properties. Continuous polyimide aerogel fibers enhanced by para-aramid nanofibers (PANFs) were prepared via a novel "reaction spinning" method combined with supercritical CO2 drying. Attributed to the 3D interconnected porous structure, the polyimide-based aerogel fibers exhibit high porosity (83.0 %-85.5 %) and specific surface area (55 - 105 m2/g). Meanwhile, the continuous and flexible polyimide-based aerogel fibers reinforced by 2 wt% PANFs possess good mechanical properties with an optimal tensile strength (5.3 MPa) and initial modulus (299 MPa). Additionally, the modified polyimide aerogel fibers and their textiles are endowed with good hydrophobicity and thermal insulation properties, expanding their potential thermal management applications under hygrothermal environments.