Author
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Shogren, Randal |
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Submitted to: Society of Experimental Mechanics
Publication Type: Abstract Only Publication Acceptance Date: 6/8/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: This talk will review the structure and function of common natural polymers and describe some research avenues needed to convert these materials into useful articles. Natural polymers such as cellulose, hemicellulose, lignin, starch, protein, and chitin make up the bulk of the organic matter on earth yet are not widely used compared to petroleum based polymers. This is beginning to change as industry recognizes that fossil-based carbon resources will be depleted in the future and that plant based materials offer a renewable, sustainable resource base. Biopolymers have the advantage of having very specific, uniform stereochemistries and thus form unique higher order structures. These have a diverse array of functions in nature such as energy storage, adhesives, and structural elements. Several problems arise in the conversion and processing of biopolymers due to their polar nature and hence high melting and glass transition temperatures. Other problems include slow crystallization rates, difficulty in orientation, and poor water resistance. Some approaches to these problems will be illustrated by describing some ongoing research at NCAUR. Agricultural materials such as starch can be used as low cost fillers in conventional thermoplastic polymers and, in particular, polyesters which are themselves biodegradable. Good tensile properties have been obtained for composites having loadings up to 75% starch. Starch can be melted in the presence of water or other plasticizer, compounded with fibers and other polymers into films or foams. Starch has also been chemically modified using some novel continuous processing methods to obtain materials which have improved properties for ion binding and water resistance. |
