MIT engineers create recyclable elastic yarn to tackle textile waste

A team of engineers at the Massachusetts Institute of Technology (MIT) has engineered a recyclable yarn made from polyethylene, offering a scalable solution to the global challenge of textile waste. Detailed in ACS Materials Letters, the research was led by Svetlana Boriskina, a research scientist in MIT’s Department of Mechanical Engineering, alongside first author SeongHyeon Kim and co-authors Duo Xu, Volodymyr Korolovych, Domingo Flores-Hernandez, Kaniz Moriam, and Daniel Braconnier.

The MIT team demonstrated that garments crafted from the engineered yarn can be melted down at the end of their lifecycle and respun into fresh fiber or molded into solid plastic hardware, such as buttons and belt buckles.

Overcoming the Spandex Recycling Bottleneck

Synthesized from common plastics like grocery bags and milk jugs, the new yarn replicates the hand-feel of standard sewing thread and can be woven into lightweight, stretch-fit clothing. During laboratory trials, the material endured 10 consecutive melting and respinning cycles without sacrificing structural integrity, strength, or flexibility.

The breakthrough provides a sustainable alternative to spandex-blended textiles, which dominate modern activewear but remain notoriously difficult to process in traditional recycling streams.

“Eighty per cent of textiles on the US market currently contain some amount of spandex, which makes them nonrecyclable. There’s no widely adopted technology now that recycles textiles into textiles. With our new yarn, we hope to change that.”

— Svetlana Boriskina, Research Scientist, MIT Department of Mechanical Engineering

Bicomponent Processing and Industrial Scalability

Building on prior MIT innovations in moisture-wicking and stain-resistant polyethylene fabrics, the team developed a dual-resin bicomponent architecture. The fiber features a flexible polyethylene core wrapped in a rigid outer sheath.

1. Thermal Extrusion: Commercial resin pellets are heated above their melting point—approximately 350°F (177°C)—and extruded through fine nozzles to form continuous filaments.

2. Textile Compatibility: The resulting yarn integrates directly into existing industrial knitting and weaving equipment, mirroring traditional elastomeric fiber processing.

3. Circular Economics: Post-consumer garments can be collected, melted, and processed directly back into virgin-grade fibers, drastically reducing primary polymer production demands.

“Hopefully it will prevent the need for making more and more textile materials, because you can keep recycling a large portion of it.”

— Svetlana Boriskina, Research Scientist, MIT Department of Mechanical Engineering

The research was supported by the DEVCOM Soldier Center through the US Army Research Office, the Office of Naval Research Global, and the MIT Portugal Program.

Textile-to-Textile Innovation and Circular Polyolefin Systems at Textile Recycling Focus Day

The development of single-polymer recyclable yarns, mechanical recycling of polyolefins, and the commercial scaling of circular fiber-to-fiber supply chains will be central topics of discussion at next year’s Textile Recycling Focus Day.