Scientists at MIT have developed a superplastic that is two times stronger than steel.

 

Plastic has a negative reputation. Yes, society has handled it wrong, with corporations churning out single-use items that end up in our oceans. Plastic, on the other hand, is a marvel in and of itself: light, strong, and moldable. Airplanes and electronics were made possible thanks to the invention of plastic. And, unlike glass or steel, it requires extremely little energy to manufacture.

That's why new MIT research, which was recently published in the prestigious journal Nature, is so fascinating. The team created 2DPA-1, a completely new type of plastic. Under load tests, it's two times stronger than steel, although having only one-sixth the material volume. It has the ability to conduct electricity and block gas. Because the patents behind 2DPA-1 are already being licensed by commercial firms, the material has ramifications for everything from how we manufacture the things we hold in our hands to the buildings we live in.

I called Michael Strano, an MIT chemical engineering professor and main author on the research, for a quick chemistry lesson to understand why 2DPA-1 is so sophisticated.

When you examine polymers (also known as plastics) on a molecular level, you'll notice a jumble of squiggly molecules that he compares to spaghetti. These squiggles are powerful in and of themselves. The weak point is the space between them. Those spaces are a point of failure, but they are also permeable, allowing gas to pass through. They're the reason why a ziplock plastic bag might still smell like yesterday night's meal.

“Think of a plate of spaghetti: The sauce goes deep inside,” Strano says.

The polymers in 2DPA-1, on the other hand, are arranged as flat discs rather than 3D spaghetti. These discs, which are laid out like a one-molecule-thick sheet of paper, are connected by the strongest molecule-to-molecule bond in nature: the hydrogen bond. However, you don't need to be an expert on the subject to enjoy Strano's comparison of air quotes: He calls it "2D Kevlar." The chemical relative of 2DPA-1, Kevlar, is best known for its usage in bulletproof vests.

The mechanical properties of 2DPA-1, on the other hand, are mainly interesting since the material is also very easy to manufacture. The ultra-strong 2DPA-1 may resemble graphene, another headline-grabbing two-dimensional material with seemingly unattainable properties, to those who follow materials science closely. However, graphene's limitations lie in its ability to scale outside of the lab. It's made in high-temperature ovens—we're talking 1,800 degrees Fahrenheit here—directly onto the surface of an object, with few exceptions.

Strano argues, "It's not a technique to generate bulk materials." "You put 2DPA-1 in a beaker at room temperature, and we can manufacture kilograms of this thing." In other words, the circumstances required to make 2DPA-1 are comparable to those required to make most other polymers. To manufacture thin sheets of 2DPA-1, all you need is a monomer (in this example, Strano utilized melamine found in dishes) and certain chemical solvents.

These sheets can theoretically be stacked indefinitely to create ultra-light and robust building materials that would put steel to shame. You may roll them into tiny tubes and mix them with other plastics to form composites like carbon fiber (as proven by Strano's team). However, the most immediate commercial implications for 2DPA-1 are as a barrier coating, according to Strano.

We paint everything from our cars to our homes to prevent oxidation, the rust and rot that happens when a material bonds with the oxygen in our air. But because 2DPA-1 can block gasses, “it turns out to be a very good barrier,” Strano says. Those barriers might be sold in the forms of paints or industrial coatings. They might also make their way into formulations for products like ziplock-style bags, which Strano notes could use far less material, more effectively, with 2DPA-1

To put it another way, better plastic may allow us to use less of it for the same items. Strano further points out that because Kevlar, which is molecularly close to 2DPA-1, is recyclable, 2DPA-1 should be as well. As a result, I see two possible possibilities for the plastics sector on the horizon. In one lane, we have super-strong polymers (such 2DPA-1) for long-term applications such as buildings that outperform steel while lowering carbon emissions. Other sorts of naturally sourced ultra-compostable plastics are available in the other lane, which we can discard guilt-free.