You Could Soon Be Wearing the Stuff of Plastic Grocery Bags
MIT engineers have turned polyethylene into a lightweight, moisture-wicking fabric.
Scientists at MIT have discovered a way to turn polyethylene – the stuff of plastic wrap and grocery bags – into a wearable fabric that has a surprisingly low environmental footprint. In a study published in the journal Nature Sustainability, the researchers explain how they managed to overcome a longstanding barrier to using polyethylene as a wearable fabric – its anti-wicking properties that lock in water and sweat.1
Every test revealed a material that wicks away moisture faster than other common textiles, although it does lose its hydrophilic tendency after repeated wetting. This can be stimulated once again using friction. As study co-author Svetlana Boriskina said, "You can refresh the material by rubbing it against itself, and that way it maintains its wicking ability. It can continuously and passively pump away moisture."
From an ecological perspective, this material shows promise. It is colored by adding particles to the raw powder form prior to extrusion, which means it takes on the color without the addition of any dyes or water. Said Boriskina, "We don’t need to go through the traditional process of dyeing textiles by dunking them in solutions of harsh chemicals. We can color polyethylene fibers in a completely dry fashion, and at the end of their life cycle, we could melt down, centrifuge, and recover the particles to use again."
The team used a life cycle assessment tool to conclude that producing fabric from polyethylene uses less energy than cotton or polyester. It has a lower melting point than other synthetic materials, so it doesn't need to be heated up as much to work with it. Boriskina said, "Cotton also takes a lot of land, fertilizer, and water to grow, and is treated with harsh chemicals." Furthermore, the polyethylene fabric repels dirt, does not require frequent washing, and dries rapidly.
As for any health concerns about wearing polyethylene (PE) next to the skin, Boriskina pointed out that it is biologically inert and can be softened without plasticizers.
"PE is one of the most common materials used in medical implants because it does not degrade in the body. If it's safe to put under the skin, we think it should certainly be safe to put it over the skin. In fact, owing to its chemical inertness, polyethylene is considered safe for use in cosmetic formulations. As we demonstrate in the manuscript, PE yarns can be spin-dyed with a variety of organic and inorganic colorants, which can be carefully chosen to reduce any potential health risks."
It's unclear whether or how the material sheds microplastic fibers in the wash – a serious concern with synthetics of all kinds – and Boriskina told Treehugger that that is the subject of the team's current work. "[It will be] published separately hopefully soon, and we believe that properly engineered PE fabrics can provide a sustainable upstream solution to the microplastic shedding problem."
It is intriguing research that materials scientist Shirley Meng (not involved in the study) describes as surprising but convincing: "Based on the data presented in the paper, the particular PE fabric reported here depicts superior properties than those of cotton. The main point is that recycled PE can be used to make textile, a product with significant value. This is the missing piece of PE recycling and circular economy."