MIT Engineers Develop Recyclable Elastic Yarn to Eliminate Stretch Fabric Waste
CAMBRIDGE, Mass. — Engineers at the Massachusetts Institute of Technology (MIT) have engineered a fully recyclable elastic yarn that could solve one of the textile industry’s most stubborn environmental challenges: the inability to recycle stretch fabrics.
The study, published in ACS Materials Letters, presents a mono-material elastic yarn made entirely from polyethylene—the same thermoplastic plastic commonly used in grocery bags and milk jugs. The new thread provides the stretch and strength of traditional spandex blends without their end-of-life recycling barriers.
The Challenge: Why Stretch Fabrics End Up in Landfills
An estimated 80% of textiles on the U.S. market contain some amount of spandex. Found in everything from sportswear and denim to socks and medical apparel, spandex provides necessary elasticity. However, because spandex (polyurethane) is blended with fibers like polyester or nylon, the resulting multi-material garments are nearly impossible to recycle without complex, expensive, and often toxic chemical separation processes.
As a result, millions of tons of stretch garments are sent directly to landfills or incinerators every year.
The Solution: A Mono-Material Architecture
To circumvent the multi-material recycling roadblock, the MIT research team—led by research scientist Dr. Svetlana Boriskina—engineered a core-sheath yarn built from a single chemical family:
- Stretchable Polyethylene Core: Optimized for maximum extensibility.
- Sturdy Polyethylene Sheath: Wrapped around the core to provide tensile strength and durability.
Because both components are forms of polyethylene, the entire yarn can be melted down and re-spun together without requiring chemical separation of individual layers.
“Because they are exactly the same chemistry, they play nicely together. That’s what makes this yarn very recyclable.”
— Dr. Svetlana Boriskina, Research Scientist, MIT Department of Mechanical Engineering
Tested Through 10 Recycling Cycles
To demonstrate the material’s viability, the researchers repeatedly extruded, spun, melted down, and re-spun the yarn through 10 consecutive recycling cycles.
Mechanical testing following each cycle confirmed that the re-spun fiber retained performance, strength, and flexibility comparable to the original starting yarn.
Raw Polyethylene Pellets ➔ Extrusion & Spinning ➔ Elastic Core-Sheath Yarn
│
New Garments / Molding ◄── Melted & Re-spun (10x Tested) ◄── Used Apparel
Potential Industry Impact
The manufacturing process utilizes standard industrial extrusion equipment, making it compatible with existing textile supply chains. At the end of a garment’s life cycle, polyethylene-based clothing could be processed through standard plastic recycling streams to produce:
- New textile yarns for secondary apparel production
- Molded plastic accessories such as buttons, zippers, and belt buckles
If commercialized at scale, mono-material polyethylene yarns could give brand manufacturers a direct pathway toward closed-loop, fully circular clothing production.
