Melt it, spin it, use it again

The average American throws out around 81 pounds of clothing each year, and there are few options for recycling it. MIT engineers hope to cut down on that textile waste with a new type of yarn. 

The thermoplastic yarn mimics the properties of conventional elastic yarns, which typically combine spandex with polyester or nylon. Those fibers would have to be separated for recycling—a process that isn’t practical. But the MIT team found a way to create a similarly stretchy yarn from two variations of polyethylene, a material commonly used in milk jugs and grocery bags. Because they come from the same chemical family, the yarn can be melted as is. Svetlana Boriskina, who led the work as a research scientist in the Department of Mechanical Engineering, says a garment made from this material could then be spun into new yarn for a next generation of clothing. Even after 10 cycles of melting and respinning, the yarn stays as strong and flexible as conventional thread. 

“Now we have something that can be knitted and woven,” Boriskina says. “That is the next stage.” Someday, the researchers hope, a polyethylene garment could be dropped in a collection bin and sent to a recycling facility, promoting a more sustainable, circular textile economy. 

Illustration by Rose Wong