MIT Engineers Develop Recyclable Yarn Stronger Than Spandex

MIT engineers have developed a novel recyclable yarn that could significantly reduce textile waste. This new yarn is crafted from a type of plastic commonly found in milk bottles and grocery bags. The researchers have demonstrated that garments made from this yarn can be melted down and reformed into new yarn, or even cast into accessories like buttons and belt buckles, multiple times without losing their structural integrity.

In tests, the yarn maintained its strength and flexibility even after 10 recycling cycles, performing comparably to conventional sewing thread. The team envisions this material as a direct replacement for spandex-polyester or spandex-nylon yarns, which are currently difficult to recycle due to their mixed-fiber composition. The combination of spandex with other materials prevents a unified recycling process, leading to the disposal of millions of tons of textiles annually.

Traditional elastic yarns consist of a spandex core encased in a polyester or nylon sheath. While the sheath material can be recycled, separating it from the spandex requires complex and often environmentally harmful chemical processes. This new polyethylene-based yarn, however, is designed to be recycled as a single material, bypassing the need for chemical separation and its associated costs and environmental impact.

This development builds upon previous research by the same group, which successfully spun polyethylene into yarn and demonstrated its potential for moisture-wicking and cooling properties in garments. The current study focused on optimizing polyethylene formulations to mimic the unique stretch and strength characteristics of spandex, thereby creating a truly recyclable alternative for the textile industry.