Lightweight, robust, porous heterocyclic para‐aramid aerogel hollow fibers for multifunctional applications

Abstract In nature, many fibers with warmth‐retention properties, such as the hair of polar bears and rabbits, both have a hollow cross‐section structure. The static air in fiber cavities can effectively inhibit heat conduction and serve as an effective thermal insulator. In this work, the high‐performance heterocyclic para‐aramid polymer was selected as the spinning solution, and aerogel hollow fiber was prepared by coaxial wet spinning and freeze‐drying techniques. The effects of spinning solution concentration and lyophilized solvent on the micromorphology, mechanical properties, and specific surface area of heterocyclic para‐aramid aerogel hollow fiber (HPAAHF) were systematically studied. The produced HPAAHF possessed excellent mechanical properties (tensible strength ~3.85 MPa), high specific surface area (~ 260.90 m 2 g −1 ), and lightweight advantages. The thermal conductivity of HPAAHF was only 0.0278 W m −1 K −1 , indicating its excellent thermal insulation properties. The aerogel fabric exhibited outstanding flame retardancy properties, with a total heat release of only 0.7 MJ m −2 in the cone calorimetric experiment, making it a self‐extinguishing fabric. In addition, phase change material was injected into the hollow structure to obtain aerogel‐phase change material composite fibers, which exhibited great energy storage prospects. As a result, the high‐performance heterocyclic para‐aramid polymer‐based aerogel hollow fiber was successfully prepared and had multifunctional applications in thermal insulation, flame retardancy, and heat energy storage fields.