What is commonly referred to as polyester fabric is, in fact, most often a blend of polyester and cotton. These mixed materials are extremely difficult to recycle, but recently a new solvent has been developed that can efficiently separate these components, making them almost entirely suitable for reuse.

A New Solvent for Fabric Separation

The solution, made from menthol and benzoic acid, was created by graduate student Nika Depope, Dr. Andreas Bartl, and their colleagues at the Vienna University of Technology. Although both substances are solid at room temperature, when heated to 216 °C they form what is known as a "deep eutectic solvent." When polycotton fabric (a blend of polyester and cotton) is placed in this solvent, the polyester dissolves and separates from the cotton fibers in just five minutes.

Efficiency and Preservation of Materials

During the separation process, the cotton remains undamaged: it can be washed, dried, and reused. The polyester precipitates out of the solution as it cools and is also suitable for further use. In tests, up to 100% of the cotton and 97% of the polyester were successfully recovered.

Advantages of the Method

"The most remarkable aspect of this new process is that neither the cotton nor the polyester is damaged or chemically altered," notes Bartl. "Our analyses show that the cotton fibers retain their stability and typical properties—they can even be spun into new yarn. The polyester also remains unchanged: its structure and melting point are the same as before."

Development Prospects

Currently, researchers are working to make the process more energy-efficient by lowering the required heating temperature.

The study was recently published in the journal Waste Management.