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United States Department of Agriculture

Agricultural Research Service

Title: Properties of Injection Molded Composites Containing Corn Fiber and Poly (Vinyl Alcohol)

Authors
item Cinelli, Patrizia - UNIV OF PISA, ITALY
item Chiellini, Emo - UNIV OF PISA, ITALY
item Lawton Jr, John
item Imam, Syed

Submitted to: Trade Journal Publication
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 17, 2004
Publication Date: May 12, 2006
Citation: Cinelli, P., Chiellini, E., Lawton Jr, J.W., Imam, S.H. 2006. Properties of injection molded composites containing corn fiber and poly (vinyl alcohol). J. Polymer Research, 13:107-113.

Interpretive Summary: With the increased production of ethanol from corn, the wet milling procedure has produced excessive amounts of corn fiber (CF). CF can be used as a filler in poly(vinyl alcohol) (PVA) to make plastic composites. This study investigated the effects of different amounts of CF on the properties of PVA composites. Composites containing increasing amounts of CF became stiffer and not as elastic. Surprisingly, there was no loss in strength with the increasing fiber content.The introduction of added starch into the composites also made them stiffer and less elastic, but did not lower the overall strength. Aging these composites for one year did not appreciably affect the properties of the composites. Research shows that CF, a co-product of ethanol production can be added to a synthetic polymer to produce single-use consumer plastic products.

Technical Abstract: The waste management problems and the need for environmentally compatible materials have raised the interest on the utilization of waste and co-products from agricultural industry. Composites based on natural polymers alone are extremely sensitive to water. Their mechanical properties deteriorated upon the absorption of water, limiting their usefulness in practical applications. Ongoing research cooperation between USDA and the University of Pisa, Italy, has yielded several composites based on poly(vinyl alcohol) (PVA) and corn fibers (CF). CF and PVA were processed in variable amounts in the presence of both dry and liquid plasticizers, glycerol and pentaerythritol. Cornstarch was introduced in the formulation to further increase the composition of natural components in the composites. Composites made with 30% PVA were injection molded into sample bars. Addition of starch moderately reduced elongation from 600% to 400%, and Young's modulus increased from 36 MPa to 100 MPa. The ultimate tensile strength remained constant at about 8 MPa. Composites showed little change in their mechanical properties when conditioned at various relative humidities, or after soaking in water. After storage for one year at 50% relative humidity and 23°C, composite exhibited mechanical properties similar to those of freshly prepared samples.

Last Modified: 7/31/2014
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