Companies in the United States, the United Kingdom and Portugal are seeking a process for making low-cost carbon fiber for automakers. ORNL has agreements with the companies to compare conventional and advanced processes for transforming petroleum-based PAN and similar materials into carbon fibers. Kline, Inc., estimates that textile-grade fiber, like that woven into carpets, sweaters and socks, can be converted to carbon fiber at a cost of ~$4.70 a pound.
ORNL researchers also are testing the ability of advanced processes to produce affordable carbon fiber from lignin, a renewable material that is separated from paper-mill cellulose and cheaper than PAN. Carbon fiber made from this process is estimated to cost $3.80 to $4.20 per pound, still some distance from the low end of DOE's $3 to $5 per pound target.
Fred Baker heats and spins lignin in a melt spinner. Owing to a purification process developed at ORNL, the tiny holes in the spinnerette through which hairlike fibers are drawn are not blocked by sulfur salts and particles normally present in lignin. ORNL, Pacific Northwest National Laboratory and MeadWestvaco are jointly developing an industrial process for purifying lignin to reduce material cost.
Felix Paulauskas heats bundles of fibers in a controlled manner in a furnace. The microwave-assisted plasma (MAP) techniques he helped develop eliminate the nitrogen and hydrogen atoms in the precursor, lining up the carbon atoms to produce a graphite-like fiber that is stiff and strong. Paulauskas also uses the advanced MAP techniques to reduce the costs of carbonizing and graphitizing carbon fibers.
An orange robot sprays the fibers and a binder onto a form, making a mat-like, carbon-fiber composite preform. In production the form would have the shape of an automotive part, such as a car's body panel.—Carolyn Krause
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