Corn and eggshells may soon be the manufacturing base for shoes and tyres, following advances in techniques and research.
Sportswear maker Reebok will start making shoes out of plants, beginning with a shoe with an organic cotton-made upper and a base originating from corn. This will be the first in its “Cotton + Corn” line, the company announced.
It should be on the market later this year.
The idea is that the shoe can be composted after use to grow material for new footwear.
Bill McInnis, head of Reebok Future, said: “We’re using materials that grow and can be replenished, rather than the petroleum-based materials commonly used today.
“So we’ve focused on plant-based materials such as corn and cotton at the beginning, and compostability in the end. We want to take the entire cycle into account; to go from dust to dust.”
Meanwhile, researchers at The Ohio State University found that food waste can partially replace the petroleum-based filler used in manufacturing tyres.
Katrina Cornish, endowed chair in biomaterials, has developed a method for turning eggshells and tomato skin into replacements for carbon black, a petroleum-based filler that makes up about 30% of tyres.
“The tyre industry is growing very quickly, and we don’t just need more natural rubber, we need more filler, too,” she said.
“The number of tyres being produced worldwide is going up all the time, so countries are using all the carbon black they can make. There’s no longer a surplus, so we can’t just buy some from Russia to make up the difference like we used to.”
Cornish said around half of the 100bn eggs consumed in America each year are cracked open in commercial food factories, which pay to have the shells hauled to landfills – providing a good potential source of the material.
And tomato skins, which have been bred to be thick and fibrous to survive being packed and transported, are often discarded when tomatoes are used industrially.
Researchers found that replacing different portions of carbon black with ground eggshells and tomato skin caused varying effects on rubber, increasing strength or flexibility depending on the mixture.
“We may find that we can pursue many applications that were not possible before with natural rubber,” Cornish added.
The new material has a reddish brown colour, which varies depending on the amount of eggshell or tomato in it.
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