Researchers at the University of St Andrews have unveiled two breakthrough techniques for chemically recycling and upcycling nitrile‑rubber products, such as disposable gloves, seals, and industrial parts, into new materials that are also capable of capturing carbon dioxide.
The development of sustainable methods for the upcycling of plastic waste is one of the most important challenges in achieving a circular economy and can play a significant role in tackling the climate crisis.
Among various plastics that need to be recycled, nitrile butadiene rubber (NBR) has received comparatively little attention, despite a large market of 36 million tons or $2.5 billion globally per year. NBR has wide applications ranging from disposable gloves to hoses, seals, and circular seals used to prevent leaks.
NBR is challenging to recycle due to its thermoset nature, with less than 2% currently recycled, often through low-value downcycling.
However, in a paper published today (19th March) in Angewandte Chemie, researchers from the School of Chemistry at St Andrews, introduce two new ways to chemically recycle NBR and turn it into useful new materials.
By using a ruthenium catalyst and hydrogen gas, researchers were able to "unlock" the chemical bonds in NBR and convert it into either polyamines or polyols, depending on the reaction conditions. Remarkably, the process to make polyamines works at temperatures as low as 35 °C, while making polyols requires higher temperatures but achieves excellent efficiency.
Additionally, the resulting polyamines were shown to capture CO₂, with their amine groups binding carbon dioxide to form stable compounds, a process widely employed in industrial carbon-capture technologies. This opens the possibility of using recycled materials to remove CO₂ from emissions or the atmosphere, combining plastic recycling with climate action.
Sustainable chemical recycling or upcycling routes to convert NBR into valuable chemicals or materials would be a huge leap towards greater sustainability
Lead author Dr Amit Kumar from the School of Chemistry said: "We are thrilled by this discovery, which lets us turn nitrile glove waste from chemistry labs into valuable new materials. With further development, this technology could tackle two of the planet's biggest waste problems at once: plastic pollution and carbon dioxide emissions."
