Effects of Wheat Gluten and Milled Rubber Wood Fly Ash on the Properties of Starch-based Bioplastics

Abstract

     The objectives of this work were to investigate and compare the changes produced in the properties of thermoplastic starch by loadings of wheat gluten and a combination of wheat gluten and milled rubber wood fly ash. Glycerol was used as a plasticizer and the samples were prepared by compression moulding. The wheat gluten and milled rubber wood fly ash loadings were fixed at 10 and 2.5 wt.%, respectively. Tensile tests showed that the addition of wheat gluten increased the flexibility of the thermoplastic starch, while a loading of combined wheat gluten and milled rubber wood fly ash enhanced its rigidity. Moisture adsorption and the degradation process did not vary to any significant extent in response to wheat gluten alone, but both were reduced by the addition of wheat gluten and milled rubber wood fly ash combined. This was ascribed to the effect of the milled rubber wood fly ash, which altered the basic environment of the thermoplastic starch matrix induced wheat gluten crosslinking, thereby hindering the penetration of water. SEM images revealed that the morphology of the thermoplastic starch changed as a function of variations in its composition.