MIT Develops Recyclable Polyethylene Yarn to Tackle Textile Waste

en.Wedoany.com Reported - A research team at the Massachusetts Institute of Technology (MIT) has developed a recyclable polyethylene yarn, from which garments can be melted and re-spun into new fibers after use. The findings have been published in ACS Materials Letters.

The paper is co-authored by Svetlana Boriskina, a research scientist in MIT's Department of Mechanical Engineering, first author SeongHyeon Kim, as well as Duo Xu, Volodymyr Korolovych, Domingo Flores-Hernandez, Kaniz Moriam, and Daniel Braconnier.

The research team noted that the yarn is sourced from widely used plastics such as milk bottles and shopping bags, feels similar to traditional sewing thread, and can be woven into stretchy, lightweight garments. In the U.S. market, 80% of textiles contain some amount of spandex, which renders them non-recyclable; currently, no widely adopted technology can recycle textiles back into textiles. Boriskina expressed hope that this new yarn could change that landscape. The yarn can serve as a substitute for spandex-polyester or spandex-nylon elastic yarns, whose blended fibers typically cannot be recycled together.

This research builds on an earlier polyethylene-based yarn developed by Boriskina's team, which already featured moisture-wicking and stain-resistant properties. The new yarn uses a polyethylene-based resin as the core and a harder resin as the sheath, with the core providing flexibility; the two resin pellets, purchased from chemical suppliers, are heated above their melting point (around 350 degrees Fahrenheit) and melted, with the melt extruded through fine holes to form fibers.

In laboratory recycling tests, the researchers subjected the yarn to multiple recycling cycles, and the yarn retained its original strength and flexibility after 10 rounds of melting and re-spinning. Post-use garments can either be re-spun into fibers or processed into plastic components such as buttons and belt buckles.

According to the research team, this polyethylene yarn can be produced on an industrial scale and woven into textiles just like spandex fibers. Boriskina added that, since most of the material can be continuously recycled, it will help reduce the need to constantly manufacture new textile raw materials, promoting a circular economy model in the apparel and textile industry.

Part of the research funding was provided by the DEVCOM Soldier Center through the U.S. Army Research Office, the U.S. Naval Research Global Office, and the MIT Portugal Program.