This paper describes a new technology to produce biopolymer composites at room temperature. During the process, micrometer-scale raw material is coated with zein that has strong adhesive property, which is then compressed to form a rigid material. Since this technology does not require purification of the raw materials, various types of compounds can be used as component materials. The coating of particles with zein makes use of the unique property of zein in aqueous ethanol solution. Zein molecules adsorb to the surface of hydrophilic particles when the ethanol content of solvent mixture increases. Formation of aggregates is followed to form large agglomerates. Removal of solvents from the agglomerates yields the final product. Biopolymer composites thus formed showed a broad range of compressive strengths depending on the hardness of the starting raw material used as a base component.
Kim, S., Xu, J., & Liu, S. (2010). Production of biopolymer composites by particle bonding. Composites Part A: Applied Science and Manufacturing, 41(1), 146–153. https://doi.org/10.1016/j.compositesa.2009.09.019