Author
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Shogren, Randal |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 12/1/2006 Publication Date: 3/29/2007 Citation: Shogren, R.L. 2007. Mechanical properties of oriented high amylose starch films: orientation by drawing of starch triacetates followed by deacetylation [abstract]. American Chemical Society. Paper No. 175. Interpretive Summary: Technical Abstract: The effect of orientation on the properties of starch films was studied in order to determine if film strength, flexibility and water resistance could be improved. High amylose (70%) cornstarch was peracetylated, cast into films, stretched in hot glycerol 1-5 times the original length and deacetylated. Molecular orientation of the starch was confirmed by measurement of increasing birefringence with increasing draw ratio. Tensile strength and modulus did not change with draw ratio by elongation to break increased from about 8% to 25% as draw ratio increased from 1 to 5. SEM revealed many small crazes in the drawn films, suggesting that the improved film toughness was due to energy dissipation during deformation of the crazes. Annealing of drawn films at 100% humidity resulted in partial crystallization and improved water resistance. |
