ACRES (Affordable Composites from Renewable Sources)
A multidisciplinary team is investigating the use of soybean
triglycerides as raw materials in the synthesis of new polymers suitable
for liquid molding processes. Several patent disclosures have been filed
on these novel new materials. The ACRES program taps
into a variety of research fields ranging from genetic engineering, food
science, composites manufacturing science, and materials synthesis to
mechanics, advanced materials characterization, and computer simulation.
Background
The synthesis of structurally strong polymers from renewable
resources is attractive from both the commercial and environmental
perspectives and supports global sustainability. In contrast
to typical petroleum-based composite matrix resins such as vinyl
esters, polyesters, and epoxies, soy-based composites are optionally
biodegradable; as plant oils, they contain fatty acid residues
that are readily attacked by lipase-secreting bacteria. They
can also be made into long-lasting, durable materials.
The precedent for this research was set some 60 years ago,
when Henry Ford made his first fiberglass composite auto body
using a plastic matrix derived from soybean products in 1938.
Formulated with soy proteins, these materials were found to be
highly resistant to impact.
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Reactions of soyoil enable
the production of various functionalized monomers for RTM such
as epoxidized soyoil.
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Research
Progress to date on the research includes
- Identification of the processing requirements to produce
affordable high-volume fiber-reinforced composite materials from
soy products by resin transfer molding and related molding techniques.
- Establishment of composite property-cost targets based on
commercial glass/vinyl-ester rigid composites.
- Application of characterization methods for determining the
chemical composition of soy products to quantitatively determine
the available functional groups for polymerization reactions.
- Exploration of a broad range of chemistries to convert soy
products to composite resins. Several have been found to be potential
candidates in terms of affordability and processing-property
targets, and an optimal set is being explored.
- Fabrication of the first composites using both raw soyoil
and epoxidized soyoil.
Applications
Potential applications of these innovative materials include
- Automotive industry--the impact here would be significant, as some
10 million cars are disposed of annually
- Farm machinery and vehicles
- Construction industry, where soy-based composites reinforced with
natural materials like straw could replace wood composites
- Hurricane resistant roofs-where the entire roof can be molded in place by
the VARTM process using low cost natural fibers and soy resin
- Electronic materials, where hollow keratin fibers derived from avian
sources are used as the fibers in soy resin panels to produce very low
dielctric constant materials
- Defense, where lightweight, inexpensive, disposable materials are
needed
- Rubber, foam, and flexible polymer applications
- Coatings-where the genetically engineered resin can have unique properties
Future Impact
A number of research groups are now designing and growing
genetically engineered soybeans that produce oils with hitherto
unattainable levels of unsaturation. The ACRES project stands
to make a significant contribution to the use of these new oils
in high-tech fields such as composites. The current work is also
aimed at developing an effective methodology for the analysis
of future resin systems based on renewable resources.
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