The bobbins Washington State University textile scientist Hang Liu examines are twined with something new: lustrous fibers with vibrant colors made from old T-shirts and jeans. This isn’t recycled cotton; this is regenerated cellulose—one of the main molecules in plants, including cotton—in new fibers reincarnated from cast-off garments.
That’s a big deal, as the Marie Kondo “tidying up” effect circles the globe and people clear their closets of unwanted clothes. Those garments, with all good intentions, might end up on the racks of thrift stores. But thrift stores, overwhelmed by our collective generosity, are unable to use everything we send their way and so are discarding many of those donations. In the end, our old clothes are piling up in already-choked landfills.
Cotton recycling is a long-standing challenge. The ability to do it well, and in a non-toxic way, has been called a “game changer” by at least one nonprofit that, a few years ago, offered a million Euro prize for just such a method. But current recycled fibers suffer from short staples—broken, uneven fibers. The long fibers in the original cotton fabric are broken down by the mechanical process that aims to give them new life. Short staples are hard to spin and so virgin cotton fibers must be added to the mix. The best recycled cotton is only about 30 percent recycled material.
With Liu’s process, she says, “We dissolve the fibers down to the molecular level. What we produce are brand new fibers, very long and lustrous. And because it’s new, it’s clean.” That last bit is key to an industry in which, Liu adds, “people worry about contamination.”
Whether virgin or recycled, everybody who deals with cotton is concerned about contamination. Virgin cotton often contains residues from other plants, and rocks and sand from loading docks—even workers’ hair gets in to the mix during the spinning process. And strands of the ubiquitous plastic HDPE also get into the process at every step. With recycled cotton, the list of contaminants grows to include stitching thread (often nylon or polyester) and spandex.
Liu’s method of regenerating cellulose is non-toxic. “Cellulose is really hard to dissolve,” she says. “With the existing methods, toxic chemicals are used to dissolve it. But our chemicals are nontoxic. It’s a common solvent, and we control the dissolving conditions to make the process work well.” Even better, the chemicals used in the dissolution bath can themselves be recycled and reused in other processes.
And while her process does use water, it’s minimal compared to the 10,000 liters of water it takes to make a kilo of cotton fabric. You can look at a T-shirt as nearly a month’s supply of drinking, cooking, and washing water for an adult.
Liu speculates that her process is still a couple years from being scaled up to the commercial level. Going from the lab bench to manufacturing dresses, skirts, and T-shirts is full of engineering challenges. But Liu already has major players in the clothing industry interested.
“There’s a lot we can do to customize the fiber,” Liu says. Flame retardants could be added, as could antimicrobials for hospital gowns. The feel of the fiber can be customized, too. And the dyes used in the original materials can be retained, making highly marketable limited-edition colors possible.
“Whatever you use cotton for, you can use this regenerated fiber,” Liu concludes.
More on regenerated fiber research at the WSU Department of Apparel, Merchandising, Design & Textiles.