TU Wien Scientists Develop Breakthrough Method To Fully Recycle Blended Textiles

In a major advance for textile sustainability, researchers at TU Wien have unveiled a novel recycling method capable of almost perfectly recovering both cotton and polyester from blended fabrics, one of the industry’s most challenging waste streams. The innovation comes at a time when global textile production has surged to more than 100 million tonnes annually, making efficient recycling processes increasingly critical.

Blended textiles, such as cotton–polyester fabrics, are widely used but notoriously difficult to recycle because the fibres are tightly integrated and require complex separation. Traditional methods often rely on harsh chemicals or processes that break down polyester into smaller molecular components, resulting in material loss and degraded quality.

The TU Wien team, led by Nika Depope and Prof. Andreas Bartl from the Institute of Process Engineering, Environmental Technology and Biosciences Engineering, has developed an unexpectedly simple yet highly effective solution using two non-toxic substances: menthol and benzoic acid. Although both are solids at room temperature, when combined they create a deep eutectic solvent, a liquid with powerful dissolving properties.

When heated to 216°C, this solvent triggers a rapid and efficient separation process. Within just five minutes, the polyester in the textile blend dissolves completely, while the cotton fibres remain untouched. After separation, the cotton can be washed, dried and reused directly. As the solution cools, the dissolved polyester re-precipitates, allowing it to be extracted and recycled with minimal loss.

The results are unprecedented: the process achieves a 100% recovery rate for cotton and 97% for polyester, far exceeding the capabilities of conventional methods. Importantly, no chemical modification or structural damage occurs to either material. Laboratory analyses confirm that the cotton fibres retain their stability and mechanical properties including the ability to be spun into new yarn, while the polyester maintains its original polymer structure and melting temperature.

“This is the real breakthrough,” says Prof. Bartl. “We are separating the fibres without degrading them. Both materials emerge from the process essentially unchanged, which is exceptionally rare in textile recycling. The quality is preserved, and the fibres can return to the production cycle.”

While the method has been validated at laboratory scale, the research team sees strong potential for industrial adoption. The recovered fibres could be used to manufacture yarns, nonwovens, technical textiles, and other fabric-based products. Current efforts are focused on optimising the energy efficiency of the process, particularly reducing the relatively high operating temperature, which remains the main drawback from an industrial perspective.

With further refinement, TU Wien’s breakthrough could represent a major step forward in achieving circularity in the textile sector, offering a scalable, environmentally friendly solution to one of fashion’s largest waste problems.