A novel method could enable us to make cars from petroleum waste

Make it light, make it strong.
Derya Ozdemir
A circle of carbon fibers which have a diameter of about 10 micrometers.Nicola Ferralis

The solution to some of our climate woes lies directly in the search for ever-lighter, yet stronger, materials.

According to a study published in the journal Science Advances, a team of researchers at the Massachusetts Institute of Technology (MIT) devised a novel process for manufacturing lightweight fibers from a cheap and heavy byproduct of petroleum refining.

In addition to being cheap to manufacture, this new carbon fiber material also has the advantage of having compressional strength to be successfully used for load-bearing applications.

Heavier car, bigger engine, stronger brakes

The research that led to the novel method began around four years ago after the Department of Energy (DOE) requested that approaches be developed to make cars more fuel-efficient by reducing their overall weight. 

In case you haven't noticed, cars have become heavier over the years. Car weights within the same category have increased by more than 15 percent, said the scientists in an MIT press release. As a result, the DOE is encouraging the development of lightweight structural materials that are as safe as conventional steel panels but can also be made cheaply enough to replace steel altogether in modern vehicles.

While we’ve seen lightweight materials made from carbon fiber in the past, these have been more expensive to produce than comparable steel- or aluminum-based structural elements, which is why they’ve only been used in some expensive models. For example, making a pickup truck out of carbon fiber rather than steel could easily double the price. That’s partly because carbon fibers are typically made from polymers derived from petroleum, and a large part of the cost of carbon fibers rests with the polymers, as they can account for more than 60 percent of the total cost.

Petroleum pitch

Researchers of the new study hope to change that by providing a low-cost starting material and comparatively simple processing methods. In essence, the team's new method uses what's left over from the refinery process, a material known as petroleum pitch. This material is often land-filled because it is too dirty to burn. 

The procedure that is needed to make a carbon fiber from pitch “is actually extremely minimal, both in terms of energy requirements and in terms of actual processing that you need to do," according to research scientist Nicola Ferralis.

And, by adjusting the starting conditions, carbon fibers could be made that are not only strong in tension but also strong in compression. In other words, these materials could be put to use in entirely new ways. While DOE's call for projects asked for projects aiming to lower the cost of lightweight materials below $5 a pound, MIT's method is expected to do even better than that. The team estimates that it can reach about $3 a pound.

"The new route we're developing is not just a cost effect," Ferralis said. "It might open up new applications, and it doesn't have to be vehicles.

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