A new perspective published in Engineering highlights recent advances in chemical recycling of polyurethane (PU), the most prevalent thermoset plastic accounting for approximately 6.3% of global plastic production, with a focus on depolymerization methods that could support circular economy goals and reduce reliance on fossil feedstocks. This article summarizes progress in hydrogenation, acidolysis, and chem‑solvolysis, mainly applied to flexible PU foams, and discusses remaining challenges for industrial‑scale implementation.

Conventional mechanical recycling and incineration of PU waste lead to downgraded materials or toxic emissions, while established chemical methods such as glycolysis produce polyols of lower quality that cannot fully replace virgin feedstocks and fail to recover isocyanate precursors. The authors review improved approaches where cross‑linked PU networks are selectively broken down to recover polyols and aromatic amines, which can serve as building blocks for new PU materials. In catalytic hydrogenation, green hydrogen and transition‑metal catalysts cleave PU into polyols and anilines; recent work replaces noble metals with earth‑abundant manganese complexes, improving cost efficiency while maintaining depolymerization activity under moderate pressure and temperature conditions. Chem‑solvolysis using tert‑amyl alcohol (TAA) with potassium hydroxide catalysis achieves full depolymerization of flexible PU foams, yielding toluenediamine and polyols at high purity; recycled polyols from this process have been shown to fully substitute virgin polyols without formulation changes, supporting closed‑loop reuse. Acidolysis with organic diacids under solvent‑free conditions enables simplified separation of polyols and nitrogen‑containing intermediates, which can be further converted to amines via hydrolysis.

Each method shows distinct advantages and limitations related to catalyst cost, energy use, product purification, and scalability. Life‑cycle and techno‑economic assessments remain essential to evaluate environmental impacts and industrial viability. The authors note that key hurdles include efficient sorting of post‑consumer waste, cost‑effective separation of polyol and aromatic fractions, handling mixed polyol streams from end‑of‑life products, and safe valorization of anilines back to isocyanates. The findings indicate that advanced chemical recycling can move PU waste management toward greater circularity, though continued optimization and cross‑sector collaboration are needed to translate laboratory achievements into industrial practice.

The paper “Recent Advances in the Chemical Recycling of Polyurethane Consumer Products,” is authored by Anjana S. Sarala, Bjarke S. Donslund, Troels Skrydstrup. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.11.031. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.