David Hepworth and Eric Whale, two Scottish material scientists, were looking for smart ways to reuse food waste when they figured out how to make nanofibers out of carrot pulp, the leftovers from carrot juice. The cellulose in carrots and other root vegetables, unlike other fibrous materials like wood or cotton, is easy to separate out from the rest of the biowaste—they extract it from the pulp.
The scientists call the material Curran, after the Gaelic word for carrot, and set out to show that it could be used as an alternative to glass or carbon fibers. They say it's nearly twice as strong and slightly lighter than carbon. In 2007, Hepworth and Whale founded CelluComp, a company to develop Curran and other plant-based materials.
Christian Kemp-Griffin, the CEO of CelluComp, says they started with carrots because they were cheap and easy to get—they would just go buy out their local grocery store. But they soon realized that the carrot pulp actually worked well and that they could tap into agricultural waste to source their material.
First, the scientists made a fishing rod out of Curran. They figured a rod had to be light, flexible and strong—all characteristics that Curran could best bring. Called the E21 Carrot Stix, it won some awards and sold well.
Then, with grant money from the European Union to test the material, CelluComp hired researchers at EMPA, the Swiss Federal Laboratories for Materials Science and Technology, to identify the best ways to put nanofibers sourced from plants—they're looking at sugar beets next—to work. They found that the smartest, most ecologically responsible use for the nanofibers, including Curran, was for protective sporting goods, in particular motorcycle helmets which have to be both strong and light.
That's right: Motorcycle helmets of the future might be made from carrots, not carbon.
“Nanocellulose has material properties that would allow it to replace either glass or carbon in today’s plastic fiber,” says Roland Hischier, a researcher at EMPA who specializes in analyzing the life cycle of products. “Carbon fiber is a non-renewable resource. We have, sooner or later, to see how we get these materials.”
The most interesting thing about Curran, Hischier says, is how it uses food waste, which is becoming a bigger problem in Europe as commuting and fast food are more prominent. He and the rest of the team at EMPA assessed the environmental footprint and commercial viability of Curran. The study was part of an FP7 program, which funds sustainability-related projects across the EU. “The European community, in the last 5 to 6 years, has started to put some accent on the issues of sustainability,” Hischier says.
To test whether something like Curran is actually viable, EMPA developed a three-step process. First, is there actually a need for this material? Will it be replicable and consistent outside of the lab? And, lastly, is it actually an improvement, environmentally speaking, from current materials? This is a baseline, and EMPA is working to come up with a framework for how any new renewable material will be assessed.
“The question here, first of all, was to see what could be a potential market for such a new fiber, from an ecological point but also from the economic and technical angles too,” Hischier says.
That’s where the helmet comes in. In their analysis, EMPA found that protective sporting goods, which need stiff, strong, light fibers and low economic overhead, were some of the best use cases for Curran. Hischier and his team are also looking at the viability of using it in surfboards and insulation for mobile homes. The challenge now is taking the material from the lab to production, and making sure that it’s still ecologically smart on a grander scale.
It doesn’t make sense to develop a material from biowaste if there’s no use for it, or if turning it into a useable product takes more energy than the non-renewable alternative.