ARS | Publication request: Synthesis of Zein Derivatives and Their Mechanical Properties

Submitted to: American Chemical Society Annual Meeting Symposium Proceedings
Publication Type: Proceedings/Symposium
Publication Acceptance Date: November 10, 2003
Publication Date: February 16, 2005
Citation: Biswas, A., Sessa, D.J., Gordon, S.H., Lawton Jr, J.W., Willett, J.L. Synthesis of zein derivatives and their mechanical properties. American Chemical Society Annual Meeting Symposium Proceedings. 2005. v.1.p.20.

Interpretive Summary: Corn is an abundant renewable resource that has been useful to produce about 2 billion gallons of ethanol in 2002. Co-products of its manufacture must be better utilized to make ethanol production economically feasible with less reliance on government subsidy. Annually about 500 metric tons of zein from ethanol co-products are generated. If zein can be chemically modified to enhance its mechanical properties, zein resins, which are biodegradable, can compete with petroleum based plastics, a 50 billion per annum industry. Impacts of chemical modifications of zein mechanical properties were evaluated. These basic findings are essential to generate a better zein resin. This information should be useful to scientists in academia, government, industry and anybody who is interested in value-added products from the ethanol industry.

Technical Abstract: Zein is a naturally occurring protein polymer, obtained as a product of industrial corn processing. It could possibly be used as a coating, ink, fiber, adhesive, textile, chewing gum, cosmetic and biodegradable plastic. Thus, we sought to develop a methodology to chemically modify the zein structure so that zein mechanical properties can be manipulated. A method to prepare acyl derivatives of zein was developed. Zein was dissolved in dimethyl formamide (DMF) and acylated with anhydrides and acid chlorides. The reactions were done by reacting zein DMF solution with anhydrides at 70 degrees C or at room temperature with acid chloride. The amine/hydroxyl group of zein reacted to form ester/amide link. The structure was confirmed with proton NMR and IR spectra. These acetyl, benzoyl and butaryl amide/ester derivatives of zein were compression molded and their mechanical properties were measured. This study provided structure/mechanical property relationships for these derivatives. It was found that chemical modifications by acetylation did have little impact on the mechanical properties. We also used dianhydrides to crosslink zein. At low level, i.e. 2-5% of dianhydrides zein showed significant improvement in mechanical properties. When dianhydrides were used at a higher level the products were crosslinked and insoluble.