In what’s cleverly being referred to as “driving on eggshells,” researchers from Ohio State University have been testing tomato peels and eggshells amongst other foodstuffs for their ability to replace the filler used in tires.
The current filler used is petroleum-based and, while it works just fine in tires, it’s not sustainable and actually limits mobility for rubber. Researchers decided to tackle this problem by trying out different food products and trash items to produce an alternative filler that is sustainable. The tomato peels remain stable at high temperatures, ensuring that the tires perform well, while the porous microstructures of eggshells offer a larger surface area to easily fuse with the rubber.
Not only is this food/trash waste viable, it actually makes the rubber used in tires, and possibly other products, more flexible.
“We found that replacing different portions of carbon black [filler] with ground eggshells and tomato peels caused synergistic effects — for instance, enabling strong rubber to retain flexibility,” said Cindy Barrera, co-author of the study, said in a statement.
Carbon black makes up 30% of the tires and is usually imported from overseas to the U.S., but researchers say that the supply is becoming scarce because demand is increasing while the product dwindles. So besides it being unsustainable, its declining surplus has led researchers to search for an alternative.
Since tomato peels, eggshells, and trash are plentiful in the U.S., with about 100 billion eggs alone being consumed by Americans every year, the researchers don’t see there being a problem with obtaining the supplies for their new filler. About half of those eggs are used by commercial food factories, which then send their eggshells to landfills by the ton, making it even easier to gather the necessary ‘ingredients.’
“We’re not suggesting that we collect the eggshells from your breakfast,” study lead researcher Katrina Cornish, a biomaterials researcher and professor at OSU, said in the statement. “We’re going right to the biggest source.”
While their method of turning waste into filler is awaiting approval for a patent, the researchers at OSU are trying out different combinations of the items to determine the best way to create a durable, flexible rubber.