Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2011
Publication Date: 4/18/2011
Citation: Selling, G.W., Biswas, A., Woods, K.K. 2011. Electrospun zein fibers using glyoxal as the cross-linking reagent. Journal of Applied Polymer Science. 60(4):537-542. Interpretive Summary: Historically one of the major uses of zein (one of the main co-product of bio-ethanol production using corn) was in the textile market. In order to re-enter this market, the strength and durability of zein fiber and fabrics needs to be improved. Through the use of the cross-linking reagent glyoxal, these properties are greatly improved. Fibers using zein cross-linked with glyoxal were produced on a small scale spinning set (called electrospinning). The fibers produced were typically less than 1 micrometer in diameter. The fibers typically required an additional heating step in order to maximize their resistance to being dissolved by known good solvents for zein. The strength of the non-woven like fabrics that were produced increased by more than 50% when compared to control. These results demonstrate zein can be chemically modified before spinning to provide fibers with improved properties that are valued by the market. This information will be beneficial to manufacturers of zein as well as companies interested in producing fibers using renewable materials.
Technical Abstract: Glyoxal has been used to provide zein electrospun fibers that are resistant to dissolution by known zein solvents. Durable fibers with diameters between 0.2 and 0.7 micrometers could be produced. The reaction between zein and glyoxal was carried out in acetic acid at temperatures between 25 and 60 °C at various lengths of time. If the reaction was carried out too long, gelation occurred. During the course of reaction, solution viscosity increased which resulted in an increase in the diameter of the electrospun fibers produced from these solutions. Utilizing SDS-PAGE to monitor molecular weight clearly showed chain extension and branching as the reaction proceeded. When 6% glyoxal was allowed to react with zein at 25 °C for 6 hours, the resulting fibers were durable to acetic acid as spun. Fibers displayed different secondary structure utilizing far-UV circular dichroism spectroscopy. Examination of the infrared spectra illustrated the presence of additional C-O moieties, which is consistent with the reaction proposed between glyoxal and hydroxyl groups. Zein fabrics incorporating glyoxal had improved tensile strength.