Researchers develop selective recycling process for polyester blends

Researchers at Donghua University in China have developed a chemical recycling process that can break down polyester in blended textiles while preserving more than 96% of the cotton and spandex present in the material. The findings were published in the 1 August issue of the Journal of Hazardous Materials.

The solvent-based process completely breaks down polyethylene terephthalate (PET) at 80°C within 80 minutes and recovers its main building block, terephthalic acid (TPA), at around 99% purity and 99% monomer recovery.

The researchers also tested the process on PET/cotton and PET/spandex fabrics. Unlike the polyester, the accompanying cotton and spandex fibres were largely preserved, with more than 96% of the fibres remaining intact. This is important because blended fabrics are among the more difficult materials to recycle into new textiles.

Under the optimized conditions, the PET was completely broken down at 80°C within 80 minutes. At the same time, more than 96% of the cotton and spandex was recovered with their fibre structures largely maintained.

The process also works at a lower temperature than many polyester recycling methods reported in earlier studies. Some hydrolysis and glycolysis processes require temperatures above 120°C, with certain methods operating at temperatures as high as 210°C or 250°C.