From Trash To Treads: Turning Tomato Peels and Eggshells Into Tires

Back when she lived in California, Katrina Cornish found herself wondering about those open trucks she saw carrying big loads of ripe tomatoes. Why, she thought, weren’t the tomatoes on the bottom crushed into big red puddles.

The reason, she would later learn, is that the tomatoes were bred to have tough skins that allowed them to withstand all that weight from above.

That bit of knowledge would come to serve Cornish well after she moved to Ohio State University, where she is a biomaterials researcher. Recently, she and her research team discovered that not only those tough tomato peels, but also crushed eggshells, can be effective replacements for the petroleum-based filler used in car tires.

“What you want in a filler is something really tough and strong,” she says. “That was why we looked at the tomato peels.”

The filler of choice in tires and other rubber products has long been something called carbon black, a powdery carbon product that comprises 30 percent of most tires. In fact, it’s the reason many rubber products are black. Carbon black helps makes the rubber in tires more durable.

But it is in increasingly short supply as demand for cars is rising rapidly in developing countries. At the same time, carbon black production in the U.S. has dropped in recent years as the EPA cracked down on plants emitting excessive amounts of sulfur dioxide and nitrogen oxide.

That has made U.S. rubber manufacturers more dependent on overseas companies for a product that has always been susceptible to fluctuations in world oil prices.

Read more: From Trash To Treads: Turning Tomato Peels and Eggshells Into Tires