ARS | Publication request: Blends of zein and nylon-6

Submitted to: Polymers and the Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2012
Publication Date: September 17, 2012
Citation: Selling, G.W., Biswas, A. 2012. Blends of zein and nylon-6. Polymers and the Environment. 20(1):631-637.

Interpretive Summary: In order to improve the economics of the bio-ethanol industries, developing improved uses for potential co-products of these processes are needed. One attractive material is called zein. Zein is the main protein present in the corn kernel. It has historically been used in the coatings and textile industries. With the introduction of petroleum based products its use declined. In order to re-introduce zein based products into the marketplace, an improvement in physical properties and solvent resistance are needed. One method to improve the properties of a given polymer is to blend it with another polymer. Often it can be difficult to find a polymer that is compatible with the polymer of interest. Zein was found by these same authors to be compatible with polyvinylpyrrolidone; a type of nylon. In an effort to find polymers that convey additional benefits to zein, other nylon type polymers were tested. Nylon-6 (commonly used in textiles) was found to provide compatible blends with zein. The articles produced had higher strength and improved solvent resistance. Both films and fibers were produced. This research will benefit the bioethanol industry by improving the marketability of a potential co-product of this industry and therefore making the entire process more profitable.

Technical Abstract: Blends of zein and nylon-6(55k)were used to produce solution cast films and electrospun fibers. Zein was blended with nylon-6 in formic acid solution. When the amount of nylon-6 was 8% or less a compatible blend formed. The blend was determined to be compatible based on physical property measurements, DSC and IR spectra. The materials were compared based on their tensile properties, thermal properties, morphology and solvent resistance. Using between 2 and 8% nylon-6 provided a 33% increase in tensile strength. Young’s modulus increased by over 50% in this range. In general elongation was lower for all formulations. Surprisingly the cast films having 2 – 8% nylon-6 had improved solvent resistance to 90% ethanol/water. Electrospun fibers were produced from formic acid solutions of zein and nylon-6 where the amount of nylon was 0, 2 6 and 8%. Fibers produced from 27% spinning solids had average diameters on the order of 0.5 micrometer. Reducing the spinning solids to 21% provide slightly smaller fibers however, the fibers had more defects.