A lightweight aramid-based structural composite with ultralow thermal conductivity and high-impact force dissipation

Material designs for safety protection are increasingly important due to ubiquitous impact damage and thermal hazard. Recent biomimetic architectures achieve extraordinary safeguards but exhibit a single-defense function, which remains a formidable challenge in mechanical-thermal-coupled protection. Herein, a lightweight composite (AFSG) with a shear stiffening gel (SSG)-filled aramid nanofiber (ANF) aerogel structure is developed through infiltration and lamination. Benefiting from the voids-SSG coexistence construction achieved by retaining massive microvoids in densified aerogel networks, AFSG exhibits ultra-low thermal conductivity (0.09 W m(-1) k(-1)) and high-impact force dissipation. Specifically, microvoids inside AFSG greatly block heat transfer and achieve a wide insulation temperature (-120 to 300 degrees C). SSG and the laminated-layout structure effectively attenuate 65%-79% of impact force through structure hardening, interlayer sliding, and intra-layer cracking. Such a versatile, lightweight structural composite is expected to defend against simultaneous mechanical impact and heat damage as an ideal candidate for next-generation protective materials applied in transportation, military, and aerospace fields.