Preparation and Performance Study of SiO2/PI-Based Fiber Aerogels with Microtubular Structures

Abstract Thermal insulation properties are indispensable in numerous fields, including aerospace, battery thermal management, and specialized apparel. Aerogels are considered a promising class of thermal insulation materials; however, lightweight aerogels that combine excellent mechanical properties, thermal stability, and ease of preparation remain relatively scarce. In this study, we employed a strategy combining high-speed air-jet spinning as the primary method with external electrostatic assistance as a supplementary technique to efficiently prepare a silica (SiO2)/polyimide (PI) fiber aerogel (S/P-FA) with a microtubular structure. The results show that S/P-FA exhibits low density (approximately 53 mg·cm–3), low thermal conductivity (only 37.33 mW m–1·K–1 at 100 °C), and excellent mechanical properties (breaking strength of 6.4 MPa; excellent elastic recovery after 100 compression cycles at 50% strain; mechanical properties are retained even after exposure to extreme high and low temperatures). Furthermore, this aerogel exhibits good flame retardancy and hydrophobicity, demonstrating outstanding overall performance. Since its preparation process relies primarily on high-speed air-jet spinning, the yield of S/P-FA via air-jet spinning is significantly higher than that of conventional coaxial electrospinning, enabling continuous, large-scale production. These characteristics give S/P-FA tremendous application potential in the field of thermal insulation. This work provides insights into the design and preparation of high-performance thermal insulation aerogels.