New catalyst from Kyushu University enables single-step recycling of mixed plastic waste

On July 9, 2026, researchers from Kyushu University unveiled a breakthrough catalyst that selectively degrades polyurethane in mixed plastic waste, facilitating its recycling in a single chemical step. This advancement addresses the longstanding issue of recycling complex plastic materials that are often discarded due to their inability to be effectively separated.

Revolutionizing Plastic Recycling

Plastic waste, particularly from everyday items like toys and car seats, has posed a significant challenge for recycling systems. Traditional methods often lead to contamination and unusable materials, resulting in most mixed plastic waste being incinerated or landfilled. The new catalyst developed by the Japanese team allows for the breakdown of polyurethane (PU), the sixth-most widely used polymer, while preserving other plastics like polyester and polyamide.

Professor Takanori Iwasaki stated, "PU is found in textiles, sponges, and car seats, yet it remains largely outside the reach of recycling systems. Unlike PET, it does not melt when heated, so we need to break the chemical bonds directly." This innovative approach could transform the recycling landscape for materials previously deemed too complex.

How the Catalyst Works

The research team, in collaboration with the University of Tokyo and Japan's National Institute of Advanced Industrial Science and Technology, combined an iridium-based catalyst with a phenolate salt and hydrogen gas at temperatures between 130–170°C (266–338°F). This combination allows for the selective degradation of PU while leaving polyester and nylon intact, overturning conventional chemistry principles.

Iwasaki noted, "What I find most remarkable is that it overturns what every undergraduate learns in organic chemistry." By altering the order of chemical reactivity, the team achieved a new method of recycling that simplifies the process significantly.

Real-World Applications and Future Prospects

The efficacy of the catalyst was demonstrated on various real-world products, including kitchen sponges, blended underwear, mobile phone cases, and end-of-life car seats. The method successfully broke down PU into reusable components while maintaining the integrity of polyester and nylon.

This advancement holds promise particularly in industries like vehicle recycling and mattress disposal, which generate substantial amounts of PU waste with limited recycling options. However, the team acknowledges that the cost and scalability of using iridium, a rare and expensive metal, must be addressed to make this solution viable for widespread use.

In conclusion, Iwasaki expressed hope that this research could bridge fundamental chemistry and real-world applications, extending beyond plastic waste to areas like pharmaceutical synthesis.