This innovative method is the first to recover valuable materials from both carbon fiber fabric and polymer commonly used in manufacturing.
Researchers at USC have introduced a novel method for upcycling composite materials found in car panels and light rail vehicles, tackling a pressing environmental issue in the transportation and energy industries. The findings were recently published in the Journal of American Chemical Society.
“I wasn’t convinced that we could completely recycle composite materials,” remarked Travis Williams, a chemistry professor at USC Dornsife College of Letters, Arts, and Sciences. “These materials greatly enhance the efficiency of vehicles, but the challenge lies in recycling them, often resulting in waste being sent to landfills.”
The study showcases a collaboration between Williams, Steven Nutt from the M.C. Gill Composites Center at USC Viterbi School of Engineering, Clay C.C. Wang from the USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, and Berl Oakley from the University of Kansas. They demonstrated a new chemistry method that recovers and recycles composite materials effectively, ensuring their quality is maintained.
A common material
Carbon fibers are lightweight yet extremely strong fibers made from carbon atoms. They are typically paired with a polymer matrix—a rigid, plastic-like material such as epoxy, polyester, or vinyl—serving as a binder that gives shape to the composite materials.
A carbon fiber reinforced polymer (CFRP) is a composite that includes both carbon fibers and a polymer matrix. “Our research presents the first effective method to recover high-value components from both the carbon fiber and the polymer matrix of CFRP materials,” explained Williams.
“Carbon fiber composites are everywhere,” Williams noted. “You can find them in my bicycle, my car, and even my neighbor’s prosthetic device.” These composite materials are widely used in large-scale manufacturing, with CFRPs becoming more common in the structural panels and components of cars and airplanes.
“The difficulty with CFRPs is they cannot be melted down or reformed, which complicates their recycling after their useful life has ended,” said Williams. Currently, the only recycling method available applies to just about 1% of composite waste, primarily involving burning off the polymer matrix.
Nutt, a professor of chemical engineering at USC Viterbi, criticizes this method, asserting, “We should not compromise the engineered matrix material.”
A sustainable approach
Estimates suggest that between 6,000 to 8,000 composite-containing commercial airplanes will be decommissioned by 2030, and by 2050, retired wind turbines could produce around 483,000 tons of composite waste. Williams emphasized that his laboratory’s upcycling method provides a sustainable remedy to this increasing waste dilemma: “Our approach has the potential to establish new recycling and chemical manufacturing value chains while greatly diminishing the environmental harm caused by composite materials.”
This upcycling technique preserves the carbon fibers in CFRPs, which are the material’s robust and durable elements. The team’s research shows these fibers maintain over 97% of their original strength, allowing for reuse in new manufacturing. This process uniquely extracts value from both the polymer matrix and carbon fibers, converting waste into valuable products.
Using fungi as a solution
Biotechnology plays a key role in reclaiming value from the discarded polymer matrix. The researchers also explored a specially engineered fungus called Aspergillus nidulans, originally developed in Berl Oakley’s lab at the University of Kansas. The USC team discovered this fungus can reform the composite material after the fiber recycling process reduces the polymer to benzoic acid, which serves as a nutrient for the fungus to produce a chemical known as OTA ((2Z,4Z,6E)-octa-2,4,6-trienoic acid) using a modified strain of the fungus.
“OTA has potential medical applications, such as in antibiotics and anti-inflammatory medications,” shared co-researcher Wang, a professor at USC Mann and chair of the Department of Pharmacology and Pharmaceutical Sciences. “This finding is significant as it provides a new, efficient method to transform what was previously waste into valuable items for medicinal use.”
The upcycling method illustrates the capacity for fungal biocatalysts to enhance waste materials and underscores a novel approach to recycling composite materials while recovering both fiber and matrix components as high-value outputs.
“This breakthrough is timely, given the rising demand for CFRPs,” Williams added. “With substantial increases in CFRP waste anticipated in the future, this approach offers a compelling solution for sustainable material management.”
This research received funding from several sources, including the National Oceanic and Atmospheric Administration under the Sea Grant award (NA24OARX417C0413-T1-01); the National Institute of Health (R21-AI156320); the National Science Foundation (CMMI-2134658, 2227649); USC (support from the USC Dornsife College faculty working group, Zumberge fund, and President’s Sustainability Initiative, McGill Composites Center); the USC Wrigley Institute for Environmental Studies (Innovation award); and the University of Kansas Endowment (Irving S. Johnson Fund).
