A recent biotechnological advancement demonstrates a method to dismantle and extract the matrix from carbon fiber reinforced polymers, allowing the recovered carbon fiber layers to possess mechanical characteristics that are similar to those of new manufacturing materials.
Currently, carbon-fiber materials are commonplace across various industries, appearing in items ranging from hockey sticks to commercial airplanes. With millions of tons of carbon fiber produced globally each year, researchers have been exploring practical and economical strategies for recycling this material.
However, recycling carbon fiber, which consists of strands of carbon atoms interconnected within a matrix, presents significant challenges when it comes to creating new, usable materials.
“It’s typically a woven fabric intertwined with a matrix, often composed of epoxy or polystyrene, which secures everything together,” explained Berl Oakley, the Irving S. Johnson Distinguished Professor of Molecular Biology at the University of Kansas. “You have a combination of the fabric and the matrix, so the objective is to retrieve the fabric for future use while also dissolving the matrix without producing harmful or wasteful byproducts. Ultimately, the goal is to recover value from these materials.”
Recently, Oakley and his team at KU, in collaboration with researchers from the University of Southern California, unveiled a new chemical process in the Journal of American Chemical Society that effectively breaks down and removes the matrix from carbon fiber reinforced polymers (CFRPs). This innovative technique results in recovered carbon fiber plies that have mechanical properties similar to those found in new manufacturing substrates.
A significant byproduct of matrix breakdown is benzoic acid. To further enhance the recovery process, Oakley has engineered a modified strain of the fungus Aspergillus nidulans that thrives on benzoic acid, producing a valuable compound known as OTA (2Z,4Z,6E)-octa-2,4,6-trienoic acid). As noted by Oakley and his colleagues in their recent research, “This marks the first system capable of reclaiming high value from both the fiber fabric and polymer matrix present in a CFRP.”
Oakley has had a long-standing collaboration with the lead author of the paper, Clay Wang from USC. “We have spent years working with his lab to cultivate secondary metabolites in Aspergillus nidulans,” Oakley remarked. “Secondary metabolites are compounds that fungi produce, with penicillin being one well-known example, that exhibit biological activities, such as inhibiting competitors. Our work revealed the Asperlin pathway, leading to the discovery of Asperlin, a secondary metabolite. We found that OTA is an intermediate in this pathway, making it a potentially valuable compound for industrial use.”
“OTA has the potential to be used in the creation of products with medical relevance, including antibiotics and anti-inflammatory medications,” Wang stated in a USC press release. “This finding is significant as it illustrates a new, more efficient method to transform what was once regarded as waste into valuable resources for medical purposes.”
Moving forward, Oakley mentioned his lab at KU will focus on enhancing the efficiency of their specialized fungus, with considerations for scalability and profitability in mind for the industrial application of the new carbon fiber recycling technique.
“Since the inception of this work, we’ve created strains that outperform the original ones,” he shared. “These advanced strains are likely to yield even better results; however, we still have substantial work to do to integrate these improvements into the process.”
At the University of Kansas, Oakley collaborated with graduate student Cory Jenkinson. At USC, Wang’s co-authors included Clarissa Olivar, Zehan Yu, Ben Miller, Maria Tangalos, Steven Nutt, and Travis Williams.
