Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 7/16/2010
Publication Date: 11/13/2010
Citation: Kim, S. 2010. Production of biopolymer composites by particle bonding. In: Elnashar, M., editor. Biopolymers. Rijeka, Croatia: Sciyo. p. 61-80. Interpretive Summary: With the rising concern for environmental protection, biodegradable polymers and bio-composites have attracted considerable attention as green materials and biocompatible materials. Recently, many research groups have concentrated on the development of biodegradable polymer blends or composites from agricultural commodities. Recently, a new technology for the production of biodegradable polymer composites that will potentially replace existing petroleum-based polymers was introduced at NCAUR. All the previously published papers on this new technology are incorporated in this article. Unlike conventional techniques, the newly developed particle-bonding technique requires neither extrusion nor processing at high temperatures. Instead, micrometer-scale raw materials (powders) are coated with a corn protein, and compressed to form a rigid material. Since this technology does not require purification of raw materials, various types of compounds can be used as component materials. This research describes the theoretical background and actual fabrication process for the production of degradable biopolymer composites. Scientists/manufacturers in industry and academia developing new biodegradable polymer materials would benefit from this work.
Technical Abstract: This article describes a new process, particle-bonding technology, to produce biopolymer composites from agricultural commodities. In this technology, matrix-protein complexes are formed by the interaction of micrometer-scale matrix material with an adhesive protein, zein. This spontaneous process makes use of the unique characteristic behavior of zein in aqueous ethanol solution: zein molecules adsorb to the surface of hydrophilic particles when the ethanol content of solvent mixture increases. After that, van der Waals force between matrix-protein complex particles induces the formation of even larger agglomerates. Removal of solvents from the agglomerates yields the final product. Biopolymer composites thus formed shows a broad range of compressive strengths depending on the hardness of the starting raw material used as a matrix material. Incorporation of graphite turns the composite into a conductive polymer following percolation theory. It is also shown that a wheat protein, gliadin, can be used as a low-cost substitute for zein.