A circular economy for pantyhose

Elastic, tear-resistant, and resistant to chemicals: These properties make polyamide 6 (polycaprolactam) a highly sought-after plastic for numerous products—from pantyhose in the textile industry to nets in the fishing industry. But what makes polyamide 6 so attractive in application turns out to be a serious disadvantage after use: This polymer is not biodegradable and therefore pollutes nature—polyamide fishing nets alone are responsible for ten percent of plastic waste in the oceans. In addition, the production of polyamide causes an enormous carbon footprint, as fossil raw materials and a complex process are required for the production of the starting monomer ε-caprolactam. To successfully incorporate plastic into a circular economy, researchers from the USA have developed a novel recycling process: With the help of a rare earth-based catalyst, they depolymerized polyamide 6 back into the monomer ε-caprolactam. The process works without solvents or toxic chemicals at relatively low temperatures. It thus enables efficient recovery of ε-caprolactam. As a result, it could form the basis for an environmentally friendly material cycle for polyamide.