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United States Department of Agriculture

Agricultural Research Service

Title: Mechanical and Thermal Properties of Starch-Filled Poly (D,l-Lactic Acid)/ Poly (Hydroxy Ester Ether) Biodegradable Blends

Authors
item Garlotta, Donald
item Doane, William - BIOTECHN.R&D, PEORIA, IL
item Shogren, Randal
item Lawton Jr, John
item Willett, Julious

Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 2002
Publication Date: February 28, 2003
Citation: GARLOTTA, D.V., DOANE, W., SHOGREN, R.L., LAWTON JR, J.W., WILLETT, J.L. MECHANICAL AND THERMAL PROPERTIES OF STARCH-FILLED POLY (D,L-LACTIC ACID)/ POLY (HYDROXY ESTER ETHER) BIODEGRADABLE BLENDS. JOURNAL OF APPLIED POLYMER SCIENCE. 2003. v. 88. p. 1775-1786.

Interpretive Summary: Cornstarch has been blended with poly (lactic acid) in order to improve its biodegradability and reduce the cost of the final product. Introduction of cornstarch into poly (lactic acid) leads to products with reduced, and usually unsatisfactory, mechanical properties and processability. A new plastic, PHEE was introduced into starch/poly (lactic acid) blends in order to improve their mechanical properties and processability. PHEE was found to enhance the mechanical properties and processability of starch/poly (lactic acid) blends to satisfactory levels. By introducing PHEE into starch/poly (lactic acid) blends, one can maximize the starch content of these blends, increasing the biodegradability and decreasing the cost of these blends without sacrificing their mechanical properties and processability.

Technical Abstract: Mechanical, structural and thermal properties of injection molded composites of granular cornstarch, poly (D,L-lactic acid) (PDDLA), and poly (hydroxy ester ethers) (PHEE) were investigated. These composites had high tensil strengths, ranging from 17-66 MPa. at starch loadings from 0% to 70%. (by weight) SEM micrographs of fracture specimens revealed good adhesion between the starch granule and the polymer matrix, as evidenced b broken starch granules. Adhesion of the starch granules to the polymer matrix was the greatest when the matrix PDLLA/PHEE ratios ranged from zero to unity. At a PDLLA/PHEE ratio of less than unity, as the starch content increased in the composites, there was an increase in the tensile strength and modulus, with a concurrent decrease in elongation. The effects of starch on the mechanical properties of starch/PDLLA composites show that as the starch content of the composite increases, the tensile strength and elongation to break decreases, while Young's modulus increases. In contrast, the tensile strength of starch/PHEE composites increase with increasing starch content.

Last Modified: 4/21/2014
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