Synthesis and characterization of highly flexible thermoplastic films from cyanoethylated corn distillers dried grains with solubles

Corn distillers dried grains with solubles (DDGS) can be made into highly flexible thermoplastic films without the need for plasticizers. DDGS is an abundantly available coproduct of ethanol production that is inexpensive ($80-130/ton) compared to most of the polymers used for thermoplastic applications. In this research, oil-and-zein-free DDGS was cyanoethylated using acrylonitrile, and cyanoethylation conditions were optimized to obtain high percent weight gain of up to 42%. Cyanoethylated DDGS was characterized using ¹H NMR, FTIR, DSC, and TGA. Cyanoethylated DDGS was compression molded into thermoplastic films, and the tensile properties of the films were studied. It was found that DDGS films with elongation as high as 38% and strength of 14 MPa could be obtained without the use of any plasticizers. Alternatively, films with strength as high as 651 MPa but with relatively low elongation (2.5%) were obtained by varying the extent of cyanoethylation. This research showed that cyanoethylation could be a viable approach to develop biothermoplastics from biopolymers for applications such as packing films, extrudates, and resins for composites.