Chemical and biomolecular engineers from the University of Delaware and the Center for Plastics Innovation, have created a new method for chemically separating fibers in textiles that enables them to be recycled more quickly and inexpensively than current methods.

Because modern-day clothing is composed of multiple types or blends of fibers, recycling those garments has become difficult. As such, the researchers developed a new approach for chemically separating these fibers so that they can be recycled with ease.

Illustration of the chemical full recycling process. Conversion of real mixed textile waste (polyester, cotton, spandex and nylon) using MW-assisted glycolysis and solvent dissolution. BHET, bis(2-hydroxyethyl) terephthalate; MDA, 4,4′-methylenedianiline. Source: Science Advances (2024). DOI: 10.1126/sciadv.ado6827

According to its developers, the process involves a solvent that breaks the bonds holding polyester together with other materials like nylon or cotton. The team determined that this bond-breaking process could be expedited by adding zinc oxide as a catalyst and then treating the clothes in a microwave oven.

This approach broke textiles apart in as little as 15 minutes. The process was documented to release nylons, cottons and other materials while simultaneously breaking down the polyester into BHET (and spandex into monomers) — which is an organic compound that could potentially be used to produce more polyester.

During trials on polyester/cotton and spandex/nylon blends, the team noted that the material integrity of both the nylon and the cotton were retained, which promises that they could potentially be used to make new batches of clothes.

The team also reported that that flame retardant chemicals used to treat clothes interfered with the process, and an approach for removing them ahead of recycling will need to be devised.

An article detailing the process, “Chemical recycling of mixed textile waste,” appears in the journal Science Advances.