Recycling polyester could keep textiles out of landfill

Researchers from the Queensland University of Technology (QUT) have discovered a treatment to extract and re-use polyester from polyester/wool mix fabrics, which should help prevent some of the 92 million tonnes of textiles dumped every year from going to landfill.

Associate Professor Alice Payne, from the QUT School of Design – Fashion, said Australians send 500,000 tonnes, or $140 million worth, of textiles to landfill every year, with an average lifetime of three months for each item.

“Polyester is incorporated in much of the 80–150 billion items of clothing made each year,” Assoc Prof Payne said.

“It is favoured on its own or incorporated with natural fibres like cotton or wool because it is durable, lightweight [and] easy-care with anti-wrinkle properties.”

Now, Assoc Prof Payne and her colleagues have found that a commercial enzyme dissolves wool fibres from polyester and wool mix fabrics, without damaging the polyester strands.

“Complete degradation of wool fibres was achieved by application of a keratinase in a two-step process with addition of reducing agent and undigested polyester fibres were recovered,” the researchers wrote in the journal Waste Management.

“Electron microscopy showed complete breakdown of the natural fibres in the fabric blends, while spectroscopic and mechanical analysis of the recovered synthetic fibres confirmed that the enzymatic treatment had no significant impact on the properties of the polyester compared to virgin samples. The polyester fibres are therefore suitable to be recycled to polyester yarn and re-used in the manufacture of new garments or other products.

According to corresponding author Professor Robert Speight, from QUT’s Institute for Future Environments, recycled polyester is a valuable tradable commodity.

“The polyester extracted from fabric can be made into polyester chips and turned into anything from yarn for new textiles to playground equipment,” he said.

“The value of recycled polyester has gone up significantly and gives clothing manufacturers a massive marketing advantage to be able to claim recycled material.

“Adidas, for example, has committed to using only recycled plastic by 2024, which includes polyester, contributing to the demand for recycled polyester.”

Prof Speight said the researchers’ next phase is to partner with recycling companies to take the process to kilogram scale and understand more about the process design for commercial use and the economics. Assoc Prof Payne meanwhile added that separating and re-using polyester is part of the drive to prevent waste in the fashion industry — other ways to prevent waste include using clothing longer, buying second hand rather than new and circulating, lending, borrowing, repairing, upcycling or reselling unwanted clothing.

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