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.