From Food Waste to Wheels: Researchers Turn Tomatoes Into Tires

Researchers at Ohio State University have developed a technology for incorporating food waste into rubber. Here, dried and ground tomato skins (top) and eggshells (bottom) are shown after coarse, medium and fine processing before being added to rubber. Photo by Kenneth Chamberlain, courtesy of The Ohio State University.

Researchers at Ohio State University are cooking up a plan that could mean your next set of car tires comes from food scraps.

For more than a century, manufacturers have made rubber tires with a petroleum-based filler. That filler — called carbon black — makes the rubber durable. Because its cost fluctuates with the price of oil, it can be quite pricey. Add to that increased global demand for tires, a dwindling surplus of carbon black, and the potential harm rubber creates for the environment and you have, well, a recipe for a potentially big problem.

Enter Katrina Cornish, a biomaterials researcher at Ohio State who's spent years trying to find alternative rubber sources produced right here in the U.S. Cornish has created a method for turning locally sourced food waste into carbon black.

Her patent-pending discovery — that tomato peels and eggshells may be viable replacements for carbon black — just might crack the tire manufacturing industry wide open.

According to the U.S. Department of Agriculture, Americans eat more than half a billion eggs each year. Tons more are cracked — often mistakenly — in commercial factories. The eggshells are rounded up and hauled to landfills, where their mineral composition keeps them from breaking down.

Tomatoes are an equally popular dietary staple — Americans eat more than 13 million tons (11.75 million metric tons) of the fruit annually, mostly processed as sauces or other products. Often, all that's left are the tomatoes' thick, rubbery skins that were bred to withstand tight packing and interstate hauls from farms to supermarkets — but not the human digestive system.

But what's not fitting for human consumption, Cornish found, may be black gold for the tire industry. Eggshells and the skins from commercially grown tomatoes, her team discovered, make rubber stronger and more flexible. The tomato peels remain stable at high temperatures, while eggshells have a porous makeup that provides larger surface area for contact with the rubber. The result? These alternative fillers exceed industry performance standards.

Researchers now are looking for ways to add color to the materials. Unlike carbon black, the food waste filler is reddish brown, based on the amount of eggshell or tomato used in it. And they're continuing to develop the patent-pending technology, which the university has licensed to Cornish's company EnergyEne.

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