Preparation And Properties Of The Corn Gluten Meal Biodegradable Plastics

Corn gluten meal (CGM) is the byproducts of the corn starch processing from wet milling method of the maize, and the powder can be used in many fields. But its use has been limited due to its complicated structure, poor taste and solubility, so the corn gluten meal was mainly used as feeding industry or released as a waste. The utilization abroad was merely limited in pigment industry, and studies relating making amino acid and functional peptide by enzymatic digesting of corn protein. So it has a significant meaning if the value of corn gluten meal is added by used as material of making complete bio-degradation plastic.CGM blended with glycerol which was used as the plasticizers, the mixture was extruded into pellets by the single-screw extruder, and next the pellets were hot-pressed as the specimens. The characteristics of the specimens were evaluated; the results showed that the specimen containing20%of glycerol had the better mechanical properties, the established equation based on Halsey equation could predicted the relationship between the tensile strength and relative humidity, the results showed the experimental data could better fit the equation. Observation result using scanning electron microscopy (SEM) showed that the specimen had a uniform structure. The result of thermal gravimetric analysis (TGA) considered that it can keep thermal stability below180℃. The bio-degradable experiments showed that biodegradable cycle of the CGM plastic was about4weeks.Because of the bad characteristics of the CGM specimens such as low tensile strength, moisture absorption and so on, in this study to add PLA into the based CGM plastic system to improve the mechanic properties, at the mean time, the stretch intensity and water proof capability are also enhanced as well as maintaining the complete biodegradation of the test sample.Corn gluten meal (CGM)/poly lactic acid (PLA) composites, plasticized by glycerol, ethanol solution, were extruded into pellets using single-screw extruder, and then the pellets were hot-pressed into specimens for evaluation of tensile strength, water resistance, thermal stability and morphology. The results showed that PLA reinforced the CGM composite, as well as improved the water resistance. The structure of specimen was observed by scanning electron microscopy (SEM), it was showed that PLA formed a network structure, and the modified corn protein inlay in network. The FTIR spectra showed that new molecular structure was formed that combined by the molecules of PLA and protein. The result of thermal gravimetric analysis (TGA) considered that it could keep thermal stability below180℃. The biodegradable experiments showed that biodegradable cycle of the CGM/PLA plastic was4weeks, and the addition of PLA had not prolong the bio-degradation cycle of the plastic.