ScienceDaily (Mar. 27, 2012) —
Common material such as polyethylene used in plastic bags could be
turned into something far more valuable through a process being
developed at the Department of Energy's Oak Ridge National Laboratory.
In a paper published in Advanced Materials, a team led by
Amit Naskar of the Materials Science and Technology Division outlined a
method that allows not only for production of carbon fiber but also the
ability to tailor the final product to specific applications.
"Our results represent what we believe will one day provide industry
with a flexible technique for producing technologically innovative
fibers in myriad configurations such as fiber bundle or non-woven mat
assemblies," Naskar said.
Using a combination of multi-component fiber spinning and their
sulfonation technique, Naskar and colleagues demonstrated that they can
make polyethylene-base fibers with a customized surface contour and
manipulate filament diameter down to the submicron scale. The
patent-pending process also allows them to tune the porosity, making the
material potentially useful for filtration, catalysis and
electrochemical energy harvesting.
Naskar noted that the sulfonation process allows for great
flexibility as the carbon fibers exhibit properties that are dictated by
processing conditions. For this project, the researchers produced
carbon fibers with unique cross-sectional geometry, from hollow circular
to gear-shaped by using a multi-component melt extrusion-based fiber
The possibilities are virtually endless, according to Naskar, who described the process.
"We dip the fiber bundle into an acid containing a chemical bath
where it reacts and forms a black fiber that no longer will melt,"
Naskar said. "It is this sulfonation reaction that transforms the
plastic fiber into an infusible form.
"At this stage, the plastic molecules bond, and with further heating
cannot melt or flow. At very high temperatures, this fiber retains
mostly carbon and all other elements volatize off in different gas or
The researchers also noted that their discovery represents a success
for DOE, which seeks advances in lightweight materials that can, among
other things, help the U.S. auto industry design cars able to achieve
more miles per gallon with no compromise in safety or comfort. And the
raw material, which could come from grocery store plastic bags, carpet
backing scraps and salvage, is abundant and inexpensive.
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- Marcus Hunt, Tomonori Saito, Rebecca Brown and Amar Kumbhar. Patterned functional carbon fibers from polyethylene. Advanced Materials, 2012 DOI: 10.1002/adma.201104551