Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: October 1, 2005
Publication Date: October 1, 2006
Citation: Finkenstadt, V.L., Willett, J.L. 2006. Characterization of functionalized electroactive biopolymers. American Chemical Society Symposium Series. p.256-261. Interpretive Summary: Thermoplastic starch can be made electrically conductive using metal halide salts. The mode of conductance is ionic in nature. Polymer flexibility and salt content determine the final conductance value for thermoplastic starch. This research adds value to agricultural commodities by developing advanced materials from starch.
Technical Abstract: Biopolymers have the potential for use as a matrix for applications such as controlled release devices and environmentally sensitive membranes. Renewable resources can be utilized as polymer matrices for electroactive material. Natural polymers are generally more environmentally-friendly and biocompatible than existing synthetic products. Thermoplastic starch is naturally insulative; however, the chemical, electrical, and mechanical properties of the biopolymer matrix can be tailored for specific functionality in a continuous process utilizing reactive extrusion. Conductance can be measured in the solid state by a direct-current resistance method. Ion-conducting materials, produced by doping thermoplastic starch and biopolymers with metal halides, have 3 orders of magnitude greater conductance than native materials. There is a correlation between polymer mobility and conductance. We have investigated several types of starch of different origin, derivatized starches, and plant or microbial biopolymers with ionic functional groups. The conductance approaches the level of synthetic polymer electrolytes.