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United States Department of Agriculture

Agricultural Research Service

Research Project: NOVEL STARCH-BASED MATERIALS

Location: Plant Polymer Research

Title: Novel products from starch based feedstocks

Author
item Finkenstadt, Victoria

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 17, 2013
Publication Date: June 5, 2013
Citation: Finkenstadt, V.L. 2013. Novel products from starch based feedstocks. Meeting Abstract. xx.

Technical Abstract: There has been progress in the utilization of starch as a partial replacement for petroleum based plastics, but it remains a poor direct substitute for plastics, and a moderate one for composites. Our research focuses on using polymers produced from direct fermentation such as poly(lactic acid) or microbial exopolymers made by cell-free enzymatic solutions fed by the starch-based sugars. Both of these polymers were considered to be undesirable: ethanol was preferred over lactic acid and microbial biofilms fouled equipment. Each of them are able to support their own markets for green polymer composites and anticorrosive coatings, respectively. Green polymer composites with poly(lactic acid) PLA Green polymer composites using biodegradable and bio-based polymers such as poly lactic acid and agricultural products were manufactured using twin-screw reactive extrusion and injection molding. Using agricultural “waste” as a filler, green composites were formed that showed ductile behavior. Ductile behavior is a good combination of tensile strength and flexibility. The mechanical properties of the composite are comparable to expensive thermoplastic residence, but were much more economical showing a potential for non-weight-bearing building materials or automotive interior panels. An additional use as agricultural mulch films was identified as the composite can be produced in thin sheets and has been shown to prevent weed growth, degrades in the field over a growing season. The composite can be impregnated with fertilizer or pesticide for gradual release over time. Anticorrosive coatings using biofilms Biobased polymers, produced from specific bacteria in a commercially available process, have shown to inhibit corrosion on metal substrates. Extensive electrochemical analyses showed that the exopolysaccharide, purified from cell-free cultures, adhered strongly to the metal substrate, provided active resistance to corrosive environments, and displayed limited self-healing after scratching. The coating is applied through commercial spray technology with a controlled thickness of 50-500 nm. We hypothesized the anti-corrosive ability was controlled by several properties of the environment-coating-metal system such as: 1) film-forming capability & adhesion; 2) polymer mobility as it hydrates; 3) diffusion properties through the coating; 4) ion mobility of the corrosive species through the thin film; and 5) the interfacial phenomena between environment-polymer and polymer-metal. Coating can be used as a primer or as a paint component. This technology has been submitted for patent protection by ARS and is available for licensing.

Last Modified: 9/23/2014
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