Carbon fiber reinforced polymer (CFRP) composite materials are typically disposed of in landfills or by incineration. Until now, CFRP composites have only been able to be recycled a limited number of times before they wear out, weakening the mechanical and physical properties of the materials rendering them no longer viable.
As the focus on recycling and a circular economy grows, researchers from the University of Sydney’s School of Civil Engineering saw an opportunity to improve these results by developing a new recycling process. The team designed an optimized method recycling of composite materials that could be up to 70% cheaper and lead to a 90-95% percent reduction in CO2 emissions compared to standard manufacturing while maintaining the properties of the materials.
“Until now, it has been impossible to continuously recycle products made of carbon fibers. Given that most recycling involves shredding, cutting, or grinding, fibers are worn out, decreasing a future product’s viability,” said lead researcher Dr. Ali Hadigheh. “This presents a huge challenge and threat to our environment, as it has led to the production of virgin carbon fiber which contributes significantly to greenhouse gas emissions. To combat this issue and to support a true circular economy, we developed an efficient and cost-effective method for recycling carbon fiber, which is present in tablets through to BMWs.”
Dr. Hadigheh further explained, “Pyrolysis and oxidation alone are not enough to preserve carbon fibers and these processes have existed for some time already. To ensure a high-quality recovery and economic efficiency, thermal decomposition of CFRPs need to be guided by analyzing the energy required to initiate a chemical reaction in the composite, and separate carbon fibers from the surrounding resin matrix.”
The team included parameters such as heating rate, temperature, and atmosphere to ensure the functionality and properties of the CFRP materials, assuring that high-grade, low-cost structural materials were created for use in industries including aerospace, automotive, renewable energy, and more.
“Plainly put, if we do not develop efficient and cost-effective methods to recycle carbon fiber composites, we risk damaging the environment significantly,” Dr. Hadigheh concluded.