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United States Department of Agriculture

Agricultural Research Service

Title: Biodegradable Composites of Starch and Poly(hydroxybutyrate-Co-Valerate) Copolymers

Authors
item Willett, Julious
item O'Brien, Gregory - ZENECA BIOPOLYMERS

Submitted to: Satake Centre for Grain Process Engineering
Publication Type: Proceedings
Publication Acceptance Date: June 6, 1996
Publication Date: N/A

Interpretive Summary: Approximately 20 billion pounds of plastics are used in disposable applications in the United States each year. Most of this waste is landfilled. Biodegradable polymers have been developed to allow much of this waste to be composted, but market penetration has been limited due to the high cost of these materials. The addition of starch, a low cost, biodegradable, annually renewable resource, can be used to reduce the cost of these products without sacrificing properties or biodegradability. Several approaches to utilizing starch in biodegradable plastics made of a class of polymers called PHBV, and the biodegradation characteristics of these materials, have been developed by ARS researchers. These results are of use to producers and users of biodegradable polymers who wish to incorporate starch into their formulations, thereby providing new markets for starch.

Technical Abstract: Mechanical properties and biodegradation characteristics of composites of starch with poly(hydroxybutyrate-co-valerate) (PHBV) copolymers have been investigated. Predictive equations were generated using statistical design methods for the mechanical properties of composites with starch, plasticizer, and inorganic filler. Mechanical properties were improved by treating the starch granule surface with either a coating of poly(ethylene oxide) or by graft polymerization with glycidyl methacrylate. Coating the starch reduces the rate of composite degradation in activated sludge. Starch and inorganic filler increase the rate of biodegradation in soil exposure.

Last Modified: 10/25/2014
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