Preliminary studies on converting agricultural waste into biodegradable plastics. Part II: Corncobs

Corncob powder was derivatized either by carboxymethylation, glutaration, maleiation, phthallation, or succination in order to produce anionic materials suitable for complexation with soy protein isolate. Blending each derivative with soy protein isolate resulted in instant precipitation of gels. Infrared spectroscopy of dried gels suggested that each derivative formed a complex with protein. Effects of the type and degree of corncob derivatization on the mechanical properties of solid reaction products with soy protein isolate are reported. Except in the case of succination, a lower degree of derivatization produced larger amounts of drying shrinkage and higher mechanical strengths. Carboxymethylation resulted in tensile strengths as high as 28.9 MPa, suggesting that these materials are promising candidates for biodegradable structural materials.