Bulletproof fabric laced with carbon nanotubes is stronger than Kevlar
Bulletproof fabric is both lightweight and durable
Jin Zhang Group, Peking University
A new material is so strong that a single sheet 1.8 millimeters thick could stop a bullet, making it far stronger than Kevlar and perhaps the strongest fabric ever made.
Body armor works by diffusing the energy of a projectile through a network of connected fibers. In the case of Kevlar, these fibers are made from aramids, a group of polymer chain chemicals known for their extreme strength. However, under extreme stress, these polymer chains can slip, limiting the protection they provide.
Over the past six years, Jin Zhang of Peking University, China, and colleagues have attempted to develop materials even stronger than Kevlar or Dyneema, which is a different type of polyethylene fiber and often cited as the strongest fabric in the world.
“Ultra-high dynamic strength and toughness are crucial for fibrous materials in impact protection applications,” says Zhang. “These include bulletproof armor, vehicles and aircraft.”
His team has now developed a method to align carbon nanotubes with aramid polymer chains to prevent the molecules from sliding. “Our new fiber significantly outperforms all reported high-performance macroscopic polymer fibers,” says Zhang. “Our fabric completely outperforms Kevlar.”
The new material is a “composite made of carbon nanotubes and heterocyclic aramid,” Zhang says, but he hopes to come up with a catchier name, similar to Kevlar, “at a later date.”
Since the material is stronger than Kevlar, the same bulletproof effect can be achieved with much less material. A single layer of fabric is about 0.6 millimeters thick and can reduce the speed of a bullet traveling at 300 meters per second to 220 m/s, Zhang says. “Based on energy absorption calculations, approximately three layers of fabric are enough to stop the bullet,” making a total thickness of 1.8mm. In comparison, Kevlar must be at least 4mm thick to stop this same bullet.
Julie Cairney of the University of Sydney, Australia, says the combination of aramid fibers and oriented carbon nanotubes is innovative.
“This approach could potentially be used to produce other new composites,” says Cairney. She also claims that 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 to make lighter and more effective bulletproof vests and armor, improving security without sacrificing mobility,” she explains.
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