Researchers are working to make carbon fiber more efficient. Photo credit: Debjyoti Banerjee.
In a new study published in the Review of Applied Polymer Science, Researchers at North Carolina (NC) State University (Raleigh, SC, USA) have found a way to improve the energy efficiency of part of the carbon fiber manufacturing process.
As part of this study, results were reported from an experiment where they added two bio-based chemicals found in certain fruits into a carbon fiber precursor material. They found that with the addition of the two chemicals, starting the chemical conversion process of making carbon fiber required less energy. The chemicals are sugar acids called glucaric acid and mucic acid.
“There is a growing demand for carbon fiber, and when it comes to low-cost fiber, one of the main applications is for use as a structural material in vehicles,” says Ericka Ford, assistant professor of textile engineering, chemistry and science at NC State. “In this study, we found that by adding the two chemicals into the precursor material, we can potentially reduce the amount of energy needed to complete a step in the carbon fiber manufacturing process and help reduce some costs.”
Before using the lab chemicals, the researchers turned to computer modeling to get a glimpse of what would happen when they added the two chemical compounds to the precursor material. Their interest in chemicals was first piqued after one, glucaric acid, was listed by the US Department of Energy (DOE) as a chemical of industrial importance.
“We were interested in understanding how these chemicals would interact with the precursor material, so using computer models and simulations, we were able to examine their interaction parameters even before starting lab work,” adds the co-author. of the study Hannah Dedmon, an NC State graduate student. “We’re able to slow things down and focus on atomic-level detail, which we’re blind to in the lab.”
From there, they experimentally tested the manufacture of the precursor material – polyacrylonitrile (PAN). First, a gel-like material that has a honey-like consistency was produced, then pushed through a tiny needle to form into a very fine filament. Then the PAN filaments were heated to very high temperatures, eventually converting into a structure that forms the basis of carbon fiber.
Adding chemical additives would have reduced the energy needed to start the chemical process of making the carbon structure from PAN by five times. The researchers say it could also reduce the overall cost of this step in the manufacturing process by speeding up the reaction.
“These are small molecules with functional groups that are able to start the reaction much more efficiently than if they hadn’t been in the fiber,” says study lead author Debjyoti Banerjee, a doctoral student at NC State. .
Next, the researchers plan to look at other additives, as well as possibly using computer models to predict which ones might get the most bang for their buck. “We want to look at other natural products that we could add to PAN fibers and influence their usefulness for conversion to carbon fiber,” Ford adds.
The study, “Kinetics of cyclization of gel-spun polyacrylonitrile aldaric acid sugars using the isoconversional approach,” was authored by Banerjee, Dedmon, Ford, Farzin Rahmani, and Melissa A. Pasquinelli. It was funded by the North Carolina State Chancellor’s Innovation Fund.