New
Scientist: Amit Naskar and coworkers at Oak Ridge National
Laboratory in Tennessee have found a way to convert the
polyethylene in used plastic bags and other plastic waste into
carbon fibers that can be fine-tuned for specific applications.
Published in the journal
Advanced Materials
, their method involves mixing the polyethylene with
polyactic acid, a compound derived from cornstarch or sugar
cane. Then they heat the mixture and spin it into bundles of
fibers 0.5â20 μm thick. Each fiber bundle
is dipped into an acid-containing chemical bath, where it
reacts to form a single black fiber that can't melt even at
very high temperatures. The heat, however, causes chemical
components of the fibers to turn to a gaseous state, leaving
behind a fiber composed mostly of carbon. By varying the
process, the researchers can make fibers with different cross
sections and porosities, which can be used for a variety of
applications, such as filters for water desalination or
lightweight composite materials for cars.
