Online
at:
http://www.mariettatimes.com/news/story/0927202003_new16chemfamily.asp
September
27, 2003
The
Marietta Times
(Ohio)
Examining the water we
drink:
C8 spawns chemical family
By Callie
Lyons
The Teflon-related chemical
that has become familiar to local people by the trade name C8 is named for
the eight carbon atoms in its chain. If the scientific designation of ammonium
perfluorooctanoate sounds complicated, the thousands of consumer products
and technological advances made possible by the substance are nothing short
of miraculous.
"PFOA, or C8, is not a Teflon ingredient," said Paul Bossert,
plant manager for DuPont Washington, W.Va., Works. "It is a processing
aid used in the manufacture of polyfluoromers, including those sold under
the Teflon brand."
The best explanation of DuPont's C8 begins with a look at PFOA, a chemical
under investigation by the U.S. Environmental Protection Agency for its
possible toxicity and unexplainable prevalence.
Perfluorooctanoic acid is described by the EPA as a synthetic chemical used
in the manufacture of fluoropolymers such as Teflon. Fluoropolymers have
certain extraordinary properties, resisting fire, oil, stains, grease and
water. From non-stick coatings to protective finishes, consumer applications
are numerous.
"The issue of interest to the people of Lubeck and Little Hocking is
ammonium perfluorooctoanoate in the drinking water," said Walt Stewart
of Marietta, a retired DuPont worker. "Because this is a mouthful to
say it is commonly called C8, since it is a compound that has eight carbon
atoms in a chain. Unfortunately, this is a poor abbreviation for the chemical
since there are many organic chemicals with eight carbon atoms in a chain."
Scientists use the acronym PFOA to describe the group of chemicals, of which
the principal ammonium salt, designated with the trade name C8, is the most
common. C8 is a surfactant, or detergent-like reaction aid that helps to
keep the resin being manufactured in suspension instead of forming huge
particles.
"During the reaction, the surfactant keeps the fluoropolymer particles
all negatively charged so that they repel each other," Bossert said.
"The polymer chains can continue to grow independently instead of clumping."
Fluorinated polymers themselves are not expected to contain PFOA, or be
a pathway for humans, but the EPA is taking steps to better understand this
association. Most fluoropolymer products are used in heat-treated applications
that remove the PFOA before the final product leaves the manufacturing plant.
Fluorinated telomers, which are called "short polymers" because
of a shorter chemical strand, are not made with PFOA, but
are expected to biodegrade into PFOA. Telomers also exhibit stain-
and grease- resistant properties. With the potential for thousands of consumer
product uses, among other things, telomers are commonly used in chemical
coatings in fast food packaging.
"The properties of fluoropolymers - chemically inert, heat resistant,
good electrical properties - help enable many technologies that are of value
to society," said Rob Banerjee, superintendent of DuPont Washington
Works Fluoropolymers Manufacturing. "Fluoropolymers help reduce pollution
from heavy industries such as chemical processing or power generation, protecting
people and the environment. Fluoropolymers enable the manufacture of small,
high-speed computer chips that are core to the information technology benefits
people expect at work and at home. Telecommunications cable insulated with
fluoropolymers helps reduce risk of fire and harm to people and buildings."
The most familiar use of Teflon chemistry is coated cookware, but DuPont
officials say only four percent of its production is associated with non-stick
pots and pans.
The DuPont Washington Works plant uses about 100,000
pounds of C8 a year, most of which is recycled, Banerjee said. It's
a very expensive material, so the corporation tries to recover as much as
possible for reuse. DuPont is the only domestic manufacturer
of C8 since the 3M Co. phased out its production.
Ohioan discovered Teflon out of a failed experiment
Teflon wasn't invented in Ohio, but the man who discovered it was born here.
Dr. Roy J. Plunkett discovered Teflon by accident in 1938 as a result of
a failed experiment involving refrigerator coolant. The waxy substance proved
to be the most slippery material in existence.
Plunkett was born in New Carlisle, Ohio, in 1910, the son of a poor farmer.
He attended Manchester College and received a masters and doctorate from
The Ohio State University.
He began working for DuPont Jackson Laboratory in Deepwater, N.J., as a
research chemist in 1936.
Plunkett's discovery was found to be both heat-resistant and stick-resistant.
After 10 years of research, DuPont introduced Teflon in 1949. Before his
death in 1994, Plunkett lived to see his invention applied to everything
from satellites to cookware.
The National Inventors Hall of Fame said after his discovery of Teflon,
Plunkett managed research, development and production efforts that resulted
in the creation of numerous new fluorochemical products and processes that
have become widely used in the refrigeration, aerosol, electronic, plastics
and aerospace industries. Many are
considered to be of critical importance to national defense.
