Newly manufactured fabric seeks to tackle fashion's plastic waste problem

A new type of yarn combines the stretch of spandex with the recyclability of a single type of plastic, potentially offering a more sustainable alternative for clothing production.

The yarn, described in a July 25 study published in ACS Materials Letters, is made entirely from polyethene, the plastic commonly used in products such as milk jugs and single-use grocery bags. Most stretchy fabrics today, by contrast, combine spandex, which is a flexible but relatively weak polyurethane fibre, with stronger materials such as polyester or nylon, as an article by the LiveScience publication on this development explains.

While that combination provides clothing with both stretch and durability, the chemically different fibres are difficult and expensive to separate for recycling. The chemicals used in the process can also be toxic, meaning that very little of this material is ultimately recycled. The issue is particularly significant as athletic and leisurewear has grown increasingly popular worldwide.

An estimated 80% of textiles sold in the US contain spandex, with most eventually being incinerated or sent to landfills, according to study co-author Svetlana Boriskina, a research scientist in MIT's Department of Mechanical Engineering.

To address the problem, the MIT researchers turned to polyethene, one of the world's most widely recycled plastics. They developed a soft, springy form of polyethene to serve as the yarn's stretchy core, similar to a rubber band. Around it, they wrapped a second, more rigid polyethene fibre, resembling fishing line, tightly coiled like a spring or twisted phone cord.

Because both components are made from the same type of plastic, they can be recycled together without first having to be separated.

In laboratory tests, the researchers melted a spool of the yarn and spun it into new yarn 10 times. After each cycle, they tested its strength and found that the recycled material performed as well as the original. In direct comparisons, the new yarn even outperformed commercially available spandex-polyester yarn in maximum load, meaning it could withstand greater force before breaking, according to the study.

The researchers have also demonstrated that lightweight polyethene fibres can be engineered to provide additional properties, including cooling, moisture-wicking and stain resistance, building on their earlier work developing polyethene-based wearable fabrics.

The approach could eventually extend beyond the fabric itself. Buttons, zippers and buckles could potentially be made from compatible plastics, allowing an entire garment to be melted down and remade without first having to dismantle its individual components.

By Nazrin Sadigova