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

Zimu Li ¹, Sheng Wang ¹, Liping Gong ²

⁰CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui, 230027, P. R. China.

Advanced Materials (deerfield Beach, Fla.) +

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July 7, 2025

View abstract on PubMed

Summary

Firefighter gear is enhanced with a new shear-stiffening gel (SSG)-magnesium hydroxide (MH) coating on Kevlar fabric. This advanced composite offers superior flame retardancy and impact resistance, improving firefighter safety.

Area Of Science

Materials Science
Polymer Chemistry
Textile Engineering

Background

Firefighter safety is critically dependent on advanced protective clothing materials.
Existing materials face limitations in balancing thermal protection, flame retardancy, and mechanical strength.

Purpose Of The Study

To develop an advanced composite material for firefighter clothing with enhanced anti-impact and flame-retardant properties.
To engineer an aramid Kevlar composite using a nacre-mimetic shear-stiffening gel (SSG) and magnesium hydroxide (MH) coating.

Main Methods

Fabrication of the SSG-MH-Kevlar (SMK) composite using vacuum-assisted evaporation-induced cross-linking.
Characterization of the composite's self-assembly into a lamellar structure and interfacial interactions via hydrogen bonding and boron-oxygen crosslinking.
Evaluation of thermal and mechanical properties, including combustion resistance, tensile strength, and projectile impact performance.

Main Results

The SMK composite exhibited a highly oriented, long-range lamellar structure with enhanced interfacial interactions.
Post-combustion, SMK showed a 46% reduction in thermal radiation temperature and a 4006% increase in tensile strength compared to unmodified SSG-Kevlar (SK).
SMK composite maintained shape integrity against 100 m s<sup>-1</sup> projectile impacts, unlike Kevlar and SK composites, and demonstrated superior thermal protection according to GA10-2014 standards.

Conclusions

The developed SMK composite offers superior mechanical and thermal properties, significantly enhancing firefighter protective clothing performance.
The nacre-mimetic SSG-MH coating provides exceptional flame retardancy and anti-impact capabilities.
An SMK-integrated uniform demonstrated effective defense against sustained burning and blast impacts, outperforming conventional firefighting uniforms.

Keywords:

aramid Kevlar composite fire‐fighting service flame retardancy impact resistance nacre‐mimetic structure