ARS | Publication request: Biodegradation of thermoplastic starch and its blends with poly(lactic acid) and polyethylene: influence of morphology

Submitted to: Macromolecular Chemistry and Physics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 11, 2011
Publication Date: April 11, 2011
Citation: Li, G., Sarazin, P., Orts, W.J., Imam, S.H., Favis, B. 2011. Biodegradation of thermoplastic starch and its blends with poly(lactic acid) and polyethylene: influence of morphology. Macromolecular Chemistry and Physics. 212(11):1147-1154.

Interpretive Summary: Because renewable polymers are being used as raw material in the design and development of single-use biodegradable consumer products, it is critical that we seek ways to improve their property, create novel functionalities ans learn more about their, blending, processing and biodegradability. This report highlights the blending of Extruded thermoplastic starch with other polymers such as Low-density polyethylene and polylactic acid for creating new materials suitable for biodegradable consumer packaging. These results will help provide critical information with respect to aging, performance and the disposal of biobased single-use consumer products.

Technical Abstract: The room temperature mineralization of thermoplastic starch (TPS) with a high glycerol content and its blends with low-density polyethylene (LDPE) and polylactic acid (PLA) are examined under controlled degradation conditions. These results are correlated with the morphologies and continuity behavior of the various blend systems. It is found that thermoplastic starch degrades more rapidly than native starch. Lowering the glycerol content in the TPS has virtually no effect on its biodegradation behavior. The only contribution to biodegradation of the TPS blend is from the TPS component. Blending TPS with LDPE and PLA in a co-continuous morphology at a 50/50 composition provides a significant increase in TPS surface area, which increases the biodegradation rate for the blends as compared to pure TPS. The results indicate a close relationship between morphology, phase continuity, and biodegradation behavior.