Recycling denim in a new way

ARC-supported researchers at the ARC Industrial Transformation Research Hub for Future Fibres, based at Deakin University, have found an efficient, low-cost method that can convert waste denim into useable viscose-type fibres.

Previously, researchers have used ionic liquids—liquid salts—to dissolve cotton textiles into their cellulose building blocks. The cellulose was then spun into new viscose-type fibres that could be woven into textiles. However, ionic liquids are expensive and difficult to work with due to their high viscosity.

Given these issues, Chief Investigator Dr Nolene Byrne and her research team wanted to find a way to reduce the amount of these solvents required to recycle denim.

The researchers ground three textile samples (blue denim fabric, red denim pants and a mixed-colour t-shirt) into powders. Then they dissolved the powders in a mixture that included dimethyl sulfoxide (DMSO), using much less ionic liquid than other methods.

In addition, DMSO reduced the viscosity of the ionic liquid solution, making it easier to spin the cellulose into new fibres. Because DMSO is much cheaper than the ionic liquid, the new process reduced the cost of solvent by 77 per cent.

These new low-cost methods for textile recycling present a way for industry to reduce the vast quantity of clothing waste sent to landfill every year.

	The new technique improves on existing recycling methods, which can be inefficient and expensive, and promises to reduce both landfill and the need to grow so much new cotton.

 

Image: Dr Nolene Byrne and former PhD student Dr Beini Zeng, who had a scholarship funded by the ARC Future Fibres Hub. Credit: Deakin University.