About a third of the material in the tires on your car is something called “carbon black.” Derived from petroleum, it strengthens the rubber in tires and wicks away heat to keep the rubber from melting. It’s also what makes tires black instead of the cream color of natural rubber.
But carbon black comes from petroleum, with the attendant issues of drilling, refining, toxicity, dealing with process waste, and geopolitical uncertainty.
Researchers at Ohio State University have done away with the stuff and replaced it with eggshells and tomato skins.
Eggshells are durable; they have to be to keep embryos safe in the nest. And, they’re porous, so they adhere well to rubber. Modern tomatoes have been bred with thicker skins and high-heat tolerance to protect the fragile fruit during shipping. Put the two together and you have a binding material for tires that performs as well as carbon black.
But we’d have to get used to tires that are a rusty brown instead of sleek black.