The bulletproof fabric is both lightweight and strong
Jin Zhang Group, Peking University
A new material is so strong that just a 1.8-millimetre-thick sheet of it could stop a bullet, making it far stronger than Kevlar and possibly the strongest fabric ever made.
Bulletproof vests work by spreading the energy of a projectile through a network of connected fibres. In the case of Kevlar, these fibres are made from aramids, a group of polymer chain chemicals known for having extreme strength. However, under extreme stress, these polymer chains can slip, limiting the protection they offer.
For the past six years, Jin Zhang at Peking University, China, and his colleagues have been trying to develop even stronger materials than Kevlar or Dyneema, which is a different kind of polyethylene fibre and often cited as the world’s strongest fabric.
“Ultra-high dynamic strength and toughness are crucial for fibrous materials in impact-protective applications,” Zhang says. “These include bullet-proofing armours, vehicles, and aircraft.”
Now his team has worked out a method of aligning carbon nanotubes with aramid polymer chains to prevent the molecules from slipping. “Our new fibre significantly surpasses all reported macroscopic high-performance polymer fibres,” says Zhang. “Our fabric outperforms Kevlar entirely.”
The new material is a “fabricated carbon nanotube/heterocyclic aramid composite”, says Zhang, but he hopes to come up with a snappier name along the lines of Kevlar “at a later date”.
Because the material is stronger than Kevlar, the same bulletproof effect can be achieved with much less material. A single layer of fabric is approximately 0.6 millimetres thick and can reduce the velocity of a bullet travelling at 300 metres per second to 220 m/s, says Zhang. “Based on energy-absorption calculations, roughly three layers of fabric are sufficient to stop the bullet,” making a total thickness of 1.8 mm. By comparison, Kevlar must be at least 4 mm thick to stop that same bullet.
Julie Cairney at the University of Sydney, Australia, says the combination of aramid fibres and oriented carbon nanotubes is innovative.
“This approach could potentially be used to produce other new composites,” Cairney says. She also says the manufacturing strategy is compatible with existing industrial processes, making it promising for scalable production and real-world adoption.
“For personal and military protection, these materials could be used for lighter, more effective bulletproof vests and armour, enhancing safety without sacrificing mobility,” she says.
Topics:
