Transport and Degradation Kinetics of Biobased Polymers
A relatively new area of study is transport and degradation kinetics of
bio-based polymers. Emerging bio-products (derived from renewable
bio-resources) such as Poly-Lactic Acid can be used in making many of the
day-to-day products such as plates, cups, etc. One of the interesting
aspects of these products is that they are bio-degradable. Our research,
funded by the Initiative on Renewable Energy and the Environment (IREE), aims to
better understand the transport of moisture in bio-based polymers and how they
relate to changes in crystallinity and mechanical properties. This will
then be used in optimizing the composition and manufacturing process of PLA.
The bio-based and bio-degradable polymers such as PLA (polylactide or
polylactic acid) has many potential applications, some of which are limited by
moderate moisture barrier and thermal properties. Our group at the University of
Minnesota and at Drexel University are jointly attempting a more systematic
approach to improving bio-based polymer PLA for moisture barrier applications
through chemical modifications, copolymerization, and composites Degradability
is also a key desirable property of PLA that must be maintained in the modified
biodegradable polymers. A standard protocol for comparative degradation studies
is being developed; this will allow for quantifying changes in degradability due
to modifications of PLA. Once the degradation experimental protocol is well
defined and confirmed, we then plan to study degradation under variety of
commercially relevant conditions including temperature, humidity and moisture
content. The results of the degradation studies will be used to aid in the
selection and design of co-polymerization strategies including end group
modifications, monomer selection and ratio of PLA to other monomers. These
results will then be used to further elucidate the fundamental mechanisms of
degradation as well as devising and optimizing strategies for co-polymer
development with optimal properties and performance. These results will then be
integrated with the results and analysis from sorption, transport, and
mechanical and thermal properties measurements helping develop a comprehensive
understanding and model of the structure – properties-performance relationships.
REFERENCE Cairncross R. et al. (2006) “Moisture Sorption, Transport, and
Hydrolytic Degradation, in Polylactide (PLA) Products”, poster at IREE Annual
Research Symposium.
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