Theoretical tubulanes inspire ultrahard polymers: Rice University-printed sample is full of holes but stops bullets better than solid materials.
A lightweight material full of holes is nearly as hard as diamond. The mere dents left by speeding bullets prove it. Researchers at Rice University’s Brown School of Engineering and their colleagues are testing polymers based on tubulanes, theoretical structures of crosslinked carbon nanotubes predicted to have extraordinary strength.
They fired projectiles into patterned and solid cubes at 5.8 kilometers per second (~21,000 km/h or ~13,000 mph), and the results were impressive. For the patterned cube, the bullet was stuck in the second layer of the structure, while in the solid block, cracks propagated through the whole structure.
The Rice Lab of Materials scientist Pulickel Ajayan found tubulanes can be mimicked as scaled-up, 3-D-printed polymer blocks that prove to be better at deflecting projectiles than the same material without holes. The blocks are also highly compressible without breaking apart.
As detailed in Small, the discovery could lead to printed structures of any size with tunable mechanical properties.