Bioinspired Flame-Retardant and Impact-Resistant Aramid Composites via Nacre-Mimetic Self-Assembly for Firefighting Applications.

Abstract

Frequent fire accidents pose serious threats to firefighter security, necessitating progressively stringent demands on the performance of protective materials for firefighting clothing. This work proposes an advanced nacre-mimetic shear-stiffening gel (SSG)-magnesium hydroxide (MH) coating engineered aramid Kevlar composite, which exhibits exceptional anti-impact and flame-retardant properties. The SSG-MH-Kevlar (SMK) composite is fabricated via a facile vacuum-assisted evaporation-induced cross-linking method, facilitating the self-assembly of SMK into a highly oriented and long-range lamellar structure. The hydrogen bonding and dynamic boron-oxygen crosslinking further enhance the interface interaction, thereby contributing to extraordinary mechanical properties superior to many commercially available fabrics. After combustion, SMK composite maintains its outstanding thermal and mechanical properties, demonstrating a 46% reduction in thermal radiation temperature and a 4006% increase in tensile strength compared to the unmodified SSG-Kevlar (SK) fabric. Post-fire SMK composite can withstand projectile impacts, maintaining shape integrity upon the 100 m s-1 loading, whereas both Kevlar and SK composites are penetrated. Ultimately, an SMK-integrated firefighter uniform is manufactured, providing desirable defense efficiency during continuous 1-h burning and blast impact excitations. Furthermore, SMK cloth demonstrates exceptional thermal protection and stability in accordance with the GA10-2014 standard, outperforming conventional commercial firefighting uniforms.