A group of 12 researchers at Rice University in Houston have used 3D printing to create near-bulletproof material made out of plastic. The novel materials can withstand being shot at by bullets traveling at 5.8 kilometers per second and are highly compressible without falling apart.
The materials came about when the researchers decided to test a theoretical structure called "tubulanes." This structure was predicted back in 1993 by chemist Ray Baughman of the University of Texas at Dallas and physicist Douglas Galvão of the State University of Campinas, Brazil, both co-principal investigators on the new paper.
Tubulanes are theoretical microscopic structures comprised of crosslinked carbon nanotubes and the researchers sought to test if they would have the same properties when scaled up enough to be 3D printed. It turns out they did.
The researchers proved this by shooting a bullet traveling at 5.8 kilometers per second through two cubes. One cube was made from a solid polymer and the other from a polymer printed with a tubulane structure.
The researchers reported that the solid polymer block was left with "cracks that propagated through the whole structure.” The tubulane cube, however, stopped the projectile by its second layer.
Rice graduate student and lead author Seyed Mohammad Sajadi said it was the 3D printing method that allowed the team to take advantage of tubulanes' unique properties.
“There are plenty of theoretical systems people cannot synthesize,” he said. “They’ve remained impractical and elusive. But with 3D printing, we can still take advantage of the predicted mechanical properties because they’re the result of the topology, not the size.”
The new material can have far reaching applications in any industry that requires materials that are light but tough.
“The unique properties of such structures comes from their complex topology, which is scale-independent,” said Rice alumnus Chandra Sekhar Tiwary, co-principal investigator on the project and now an assistant professor at the Indian Institute of Technology, Kharagpur. “Topology-controlled strengthening or improving load-bearing capability can be useful for other structural designs as well.”
The study is published in the journal Small.