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United States Department of Agriculture

Agricultural Research Service

Title: Mechanical Properties of Starch Filled Poly(hydroxy Ester Ether) (Phee) Biodegradable Composites

Authors
item St Lawrence, Sterling
item Willett, Julious
item Carriere, Craig

Submitted to: Society of Plastics Engineers Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 12, 2000
Publication Date: N/A

Interpretive Summary: There is a need for biodegradable disposable products, such as cutlery, in order to reduce the amount of waste thrown into landfills. These products can be made by combining starch granules with a biodegradable plastic. Starch reduces the cost since it is very inexpensive. The mechanical properties must be characterized if these materials are to be used to make commercially viable products. This includes understanding of how they fail. The goal of this study was to characterize the failure process in composite materials made of starch granules and a biodegradable epoxy. This epoxy has been shown to adhere well to starch and the resulting composites have acceptable mechanical properties. By performing specific mechanical tests over a range of starch contents, the failure mechanism of these materials has been determined. This information would be useful for any company that wished to manufacture products using these composites.

Technical Abstract: The mechanical properties of starch filled biodegradable composites have been investigated. The strength was found to be independent of the filler content below 10 vol% and above approximately 30 vol%. This behavior is due to the failure mechanism operating in these composites. The matrix, poly(hydroxy ester ether) (PHEE), adheres well to starch, and as a result, the granules do not dewet during deformation. Instead, the composites behave as a quasi-homogeneous material with increased brittleness as the filler content increases. The deformation mechanism was investigated by acoustic emission analysis and by a post-mortem examination of the fracture surfaces. This research would benefit farmers and manufacturers as value-added products of biodegradable starch.

Last Modified: 10/23/2014
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