USDA
Agricultural Research
Service (ARS) Scientists
Develop Break Thru
Process for BioPlastic
Manufacturing
BELTSVILLE, MD March
12, 2008 –
Sugar beet pulp
may help cut the
costs of making
biodegradable plastic,
Agricultural Research
Service (ARS) studies
suggest.
The pulp is a fiber-rich
byproduct of sucrose
extraction procedures
used by sugar beet
processors. Most
of the 40 million
tons of U.S. sugar
beet pulp generated
each year is used
as an inexpensive
livestock feed or
pet-food ingredient.
But ARS chemists
Victoria Finkenstadt
and LinShu Liu aim
to breathe new economic
life into the pulp.
Finkenstadt is
with the ARS National
Center for Agricultural
Utilization Research
(NCAUR) in Peoria,
Ill. Liu is with
the ARS Eastern
Regional Research
Center in Wyndmoor,
Pa. Since 2004,
they've collaborated
on a project to
convert sugar beet
pulp into a specialized
filler material
for polylactic-acid-based
plastics.
Polylactic acid
(PLA) is considered
a promising natural
alternative to petroleum
based thermoplastics
like polypropylene
because PLA has
comparable tensile
strength and other
mechanical properties,
but is biodegradable.
But PLA is costlier
because of the complex
processes required
to derive it from
fermented corn sugars,
according to Finkenstandt,
in NCAUR's Plant
Polymer Research
Unit.
Working with Liu's
team at Wyndmoor,
Finkenstadt and
her Peoria colleagues
showed that glycerol
can be used to plasticize
the pulp and reshape
its particulate
matter into tendrils.
Early tests have
been promising,
but showed that
the PLA's tensile
strength decreased
in relation to the
amount of sugar
beet pulp or plasticizer
that was added.
To get around the
problem, Liu's group
plans on chemically
modifying the pulp
so that its tendrils
and the PLA matrix
form a stronger
bond.
Potential uses
for pulp-based PLA
composites range
from nondurable
goods such as water
bottles, cups and
packaging, to lightweight
indoor-construction
materials such as
wallboard, tabletops
and pressed furniture.
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