Every year, more than 30 billion water bottles are added to America’s
landfills, creating a mountainous environmental problem. But if research at
Missouri University of Science and Technology is successful, the plastic
bottles of the future could literally disappear within four months of being
discarded.
The Missouri S&T research team is constructing new breeds of
biodegradable and bioavailable plastics in an effort to reduce the tons of
plastic waste that ends up in the nation’s landfills each year. Bioavailable
plastics contain substances that can be absorbed by living systems during their
normal physiological functions.
By combining and modifying a variety of bio-based, oil-based and natural
polymers, the team seeks to create optimal blends that can be used to make
agricultural films, bottles, biomedical and drug delivery devices, and
more.
The team is working under the direction of Dr. K.B. Lee, professor of
chemical engineering at Missouri S&T, to improve the properties of the
biodegradable plastics for real-life products. Although companies already sell
biodegradable polymers, the products are often expensive, of poor quality or
developed for specific applications. That’s why the team is investigating how
bio-based fillers, such as starch and fibers, can be included to reduce the
cost in a variety of commercial applications.
The group is also interested in incorporating glycerol – a major byproduct
of the biodiesel process – in the new plastics.
Some of the group’s new polymers incorporate renewable resources, such as
polylactic acid, which is created by fermenting starch. The group is very
interested in renewable resources because their research and development
efforts are also focused on developing efficient and cost-effective biodiesel
and corn ethanol processes.
“Different chemical and biological mechanisms are responsible for the
degradation of polymers,” says Mahin Shahlari, a chemical engineering Ph.D.
student at Missouri S&T. “For example, it’s known that polylactic acid will
degrade in 45 to 60 days if composted at temperatures between 122 to 140
degrees Fahrenheit.”
As polylactic acid degrades, the material reacts with water to decompose
into small molecules, which are then mineralized into water and carbon
dioxide.
“In general, the main end products of polymer degradation are water and
carbon dioxide,” Shahlari explains. “Polylatic acid has the potential of
replacing the regular water bottles, and we anticipate that our research could
be incorporated into that field too.
“We are not just molding and extruding commercially available biodegrable
resins. We also are incorporating nanotechnology, supercritical fluid
technology and graft copolymer compatibilization, most of which are developed
and patented by our group.”