The technology continues to evolve, but 3D printing is still mostly used for creating prototypes or parts that won’t have to endure tremendous stresses or rigorous wear and tear. That might not always be the case, however, as researchers at Rice University found a way to 3D print complex patterns resulting in plastic objects that are almost as hard and durable as diamond.
The complex crisscrossing and zig-zagging patterns that are used to build up the structures of these polymer cubes are far from random; they’re strategically calculated and engineered to give these objects their incredible strength, but can be tweaked and tuned to exhibit other amazing properties as well.
The patterns are based on tubulanes, which are theoretical microscopic structures made of crosslinked carbon nanotubes that were predicted to have remarkable properties in 1993 by chemist Ray Baughman and physicist Douglas Galvão. Tubulanes could be used to manufacture revolutionary materials that are both strong and lightweight but to date, the structures haven’t been successfully created given the challenging logistics of manufacturing with carbon nanotubes.
A compression test showed that tubulane-based materials developed at Rice University handled pressure well, collapsing without cracking. (Courtesy of the Ajayan Research Group/Rice University)
It turns out that the predicted properties of tubulanes aren’t limited to just objects that are manufactured with atomic-scale structures. As detailed in a recently published paper in the Small journal, the Rice University researchers discovered that even when those complex patterns and structures were scaled up so that they could be recreated using 3D printers, they still exhibited those predicted properties like strength and extreme compressibility, despite being rigid structures.
The researchers blasted two cubes – one made from solid polymer, and one made from a polymer printed with a tubulane structure – with a projectile travelling at 5.8 kilometres per second (which is close to 13,000 miles per hour). Neither cube was destroyed, but while the solid polymer block was left with a huge dent and cracks propagating all the way through compromising its strength, the other cube stopped the projectile by its second layer, leaving the rest of it completely intact and undamaged.
The assumption is that a porous structure reduces an object’s stopping power, but in practice, the complex polymer lattice in these cubes makes them able to compress and collapse to absorb the kinetic energy of an impact and contain the resulting damage so that it only affects a minimal area.
This research could have wide-reaching effects on countless fields that are reliant on materials that are both lightweight and strong. Everything from aerospace, to architecture, to even the military could benefit from this new approach to manufacturing, and it could potentially even breath new life into 3D printing. Parts or components that had to be made from metal or ceramics to be adequately durable could potentially be manufactured from cheaper polymers now. Although it might take some time to convince soldiers that rolling into battle inside a plastic tank is just as safe as being surrounded by steel armour.
Featured image: Rice University