This aerogel, which is synthesised from recycled denim, shares the material properties of joint cartilage. Image credit: Deakin University.
The team, which includes Deakin scientist Dr Nolene Byrne and PhD candidate Beini Zeng, have been pioneering advanced textile recycling methods in a joint project with Deakin’s Institute for Frontier Materials (IFM) and the School of Engineering.
One of their developments has been the use of recycled textiles to form aerogels. Aerogels are a class of low density materials with a range of applications, which include water filtration and separators in advanced battery technologies.
Denim is an excellent candidate for forming aerogels because the cotton it is woven from is composed of a natural polymer, cellulose. “Cellulose is a versatile renewable material, so we can use liquid solvents on waste denim to allow it to be dissolved and regenerated into an aerogel,” explains Dr Byrne. The process is known as sol gel synthesis.
Aerogels have highly porous structures and extremely low densities. Dr Byrne describes the synthesis of the artificial cartilage aerogel as an unexpected discovery. “It has a unique porous structure and nanoscopic tunnels running through the sample. That’s exactly what cartilage looks like,” she said.
This surprising finding is particularly exciting because of the challenges involved with trying to control the properties of artificial cartilage in tissue engineering. “You can’t 3D print that material,” says Dr Byrne. “Now we can shape and tune the aerogel to manipulate the size and distribution of the tunnels to make the ideal shape.” The pores of the aerogel can be manipulated based on the drying technique – for example, supercritical CO2 drying is used to obtain an aerogel in the form of nanospheres.
The aerogels are now being tested to optimise their mechanical properties. “We are now entering pilot-scale trials and look to be at commercial scale within 3 to 5 years with industry support.”
This unique method of recycling denim will also help contribute to minimising textile waste, says Dr Byrne. “Textile waste is a global challenge with significant environmental implications, and we’ve been working for more than four years to address this problem with a viable textile recycling solution,” she said.
Textile recycling involves the use of chemicals, which can be both expensive and environmentally unfriendly. “We use environmentally-friendly chemicals, and by upcycling our approach to create a more advanced material we can address the limitations affecting other less cost-effective methods,” says Dr Byrne.
– Larissa Fedunik