— A new group of non-toxic, corrosion-resistant polymers
developed by University of Rhode Island scientist
Sze Yang will likely put a smile on the face of Erin
The polymers are designed as a replacement for chromates
in paints and other coating systems. Chromates have
been used commercially to protect metal from corrosion
for 50 years but have recently been declared hazardous.
Brockovich's efforts to demonstrate that they caused
widespread health problems in Hinckley, Cal. was made
into the Academy Award-winning movie Erin Brockovich
in 2000 starring Julia Roberts.
"There is now a worldwide push on to remove chromates
because they are carcinogens," said Yang, a professor
of chemistry and one of URI's most prolific inventors.
"Its use is gradually decreasing as replacements
The new product is a two-strand, conducting polymer
that can emulate the most important functions of chromates.
Rather than serve as a barrier coating, which are
ineffective when damaged by scratches, chromates and
the new URI polymers inhibit the process of corrosion
and are "self-healing." They promote the
formation of a protective layer and therefore can
resist scratch damage, pinholes, pitting, and stress
"Typical polymers are insulators, but conducting
polymers allow electrons to move along the polymer
chain," explained Yang, who collaborated on the
research with Richard Brown, a URI professor of chemical
engineering. "This ability to give and take electrons
is essentially the same as what chromates do -- interrupt
the electro-chemical process of corrosion formation."
Unlike other efforts to develop single-strand, corrosion-resistant
conducting polymers, this low-cost polymer has a second
strand that provides space for a variety of modifications
to its physical structure, making it more malleable
and adaptable for many application processes, including
spraying, dipping or spin coating.
Major potential markets include coating of aluminum
alloys for aircraft, aluminum and steel for the automotive
industry, and concrete-reinforcing bars for bridges,
highways and buildings. The polymers are effective
as a low-cost, minor additive to paint, and can be
soluble in commercial paint solvents and used in water-based
epoxies. It also is effective for surface treatments,
steel coil coating, and as a corrosion resistant primer
under other resin-coating systems.
Corrosion is a chemical process that causes rust and
the deterioration of metals and other materials. "We
can usually see rust easily, but the bigger problem
is the dangerous weakening effects of corrosion that
we can't see," Yang said.
In addition to their anti-corrosive properties, the
new polymers are also effective as a coating to prevent
the buildup of electrostatic charges. They can be
used in a wide variety of ways, from surgical wards
and computer chip "clean rooms" where static
can interfere with operations and production, to applications
on rugs, electrical appliances and many other products
that naturally become charged with static electricity.
They can be especially useful in operations where
combustible materials are in use, as discharges of
static in these circumstances can be a significant
Yang and Brown have been issued two patents and have
four others pending on various versions of the new
conducting polymers. Laboratory studies have been
completed on the polymer syntheses, on some test coating
formulations, and corrosion tests of coatings on aluminum
and steel. With the research complete, the co-inventors
are now seeking collaborators to commercialize the