New Method of Recycling Carbon Fiber that Causes 50% Less Degradation

It has been difficult to recycle carbon fiber up until now.

However, a UNSW Canberra researcher has developed a new method to recycle it in a way that not only means less of the material is wasted, but also uses less energy and leaves more of it intact and able to be turned into more useful new products.

Improvement on Existing Methods that Heavily Degrade Fibers

Carbon fibers are thin strands of carbon that are exceptionally strong and lightweight. The fibers are combined with plastic to create a composite which can be used to construct a variety of products.

Carbon fiber is commonly used to build aircraft, wind turbines, and it is the primary material used in Formula 1 cars, which need to be as light as possible to increase performance. You might encounter carbon fiber in high-end bicycles and other sporting equipment like hockey sticks or tennis racquets.

UNSW Canberra researcher Di He said that, until now, recycling carbon fiber had always resulted in the material being heavily degraded.

“This project was a collaboration with our partner in the automotive industry who wants to investigate building cars out of recycled carbon fiber,” explained Dr. He.

“But with the previous methods of recycling carbon fiber, the material was heavily compromised. The mechanical performance of objects made from the existing recycled fibers is degraded by 80 to 90%, compared to using new fibers.”

“Typically, it is only reused to make low-value products like tables or chairs, products that don’t experience heavy forces or loads.”

“The existing method of recycling involves shredding the composite, which destroys the carbon fiber, before heating it to remove the plastic. After it has been shredded, the fibers look like individual hairs or cotton wool strands.”

“In our method we don’t shred the carbon fiber and we optimized how we heat it in a furnace. Our method degrades the carbon fiber by less than 30%, which is a 50% improvement on existing methods.”

While the recycled carbon fiber produced using Dr. He’s method is not yet able to be used to construct a car, it is significantly closer to that goal than before. The new and improved recycled carbon fiber can potentially be used to construct individual parts of a car, such as a roof.

Reducing Waste and Energy Requirements

Car manufacturers are interested in carbon fiber vehicles as the decrease in weight would make the cars significantly more energy efficient. This would help them to meet the fuel efficiency standard announced by the Australian Government earlier this year. As we transition to electric vehicles, this would also help reduce vehicle electricity consumption, thereby increasing vehicle range.

Carbon fiber is a costly product to make, which explains the appeal of recycled carbon fiber, in addition to the environmental benefits. Recycling carbon fiber requires one-tenth of the energy needed to produce it from scratch.

One of the lead researchers from the UNSW Canberra Advanced Manufacturing Research Group, associate professor Matthew Doolan, said that as the world progressed with engineering and technological advancements, it needed to think more about reducing waste.

“As we make more advanced products we also make them from significantly more advanced materials, and as a result we are creating problems at the end of the life of that product,” associate professor Doolan said.

“Exploring other options available to us is one of the key questions we’re hoping to help answer at UNSW Canberra.”

Dr. He and associate professor Doolan, along with their collaborators, published their findings regarding recycling carbon fiber in the journal Composites Part A: Applied Science and Manufacturing.