Driving On Eggshells: Ohio State Researchers Recycle Food Scraps For Tires

Mar 14, 2017

For all their ubiquity, vehicle tires rely on an increasingly-scarce filler material known as carbon black. An Ohio State researcher says she’s found a promising replacement: eggs and tomatoes.

Katrina Cornish is a professor in Ohio State's College of Food, Agriculture, and Environmental Sciences who studies rubber biosynthesis and production. She and a team of researchers have found finely-ground egg shells and tomato peels are an adequate replacement for carbon black.

“We grind these materials down to a micro size (powder),” Cornish says. “We find that we can partially replace carbon black in tire compounds and other carbon black-filled compounds with these materials without loss of properties.”

Cornish says her material can replace carbon black entirely when it’s ground into nano-sized particles, but she says that process is too expensive to make it feasible for use in tires.

Carbon black is nearly pure carbon, but the byproduct of oil combustion is dirty to make. The U.S. Environmental Protection Agency has been pressuring carbon black makers to cut emissions.  

About 11 percent of carbon black makers have failed emissions testing in recent years, Cornish says, and the EPA has vowed to shut them down by 2020.

Katrina Cornish (left) and Cindy Barrera (right) examine ground tomato skins and eggshells and a sample of rubber.
Credit Kenneth Chamberlain/The Ohio State University.

With fewer producers supplying a constantly-growing worldwide tire industry, Cornish says tire makers will have to turn somewhere - and she hopes that'll be her.

“We’ve already taken a license into my startup company,” Cornish says.

She’s awaiting validation that her process works on a much larger scale.

That large scale would also help find a new use for egg shells and tomato peels that might otherwise be discarded. Cornish says she’s spoken with food processing plant managers who are interested in finding a new use for their scraps.

Cornish has a patent pending on her material, which is more of a reddish-brown color than a traditional tire.

If Cornish gets that large-scale validation, she says her product could be marketed to tire makers “straight away.” 

Dried and ground tomato skins and eggshells are processed before being added to rubber, and can be used to replace carbon black in wheels.
Credit Kenneth Chamberlain/The Ohio State University.