Optimization of mechanical properties of thermoplastic starch/clay nanocomposites

Starch/clay nanocomposites were prepared via solution casting method and the effects of starch source, clay cation, glycerol content, and mixing mode on clay intercalation and Young’s modulus of nanocomposites were investigated using a Taguchi experimental design approach. The clay intercalation was examined by X-ray diffraction (XRD) patterns. Nanocomposites prepared with montmorillonite (MMT) modified with citric acid demonstrated the highest Young’s modulus compared to pristine MMT and organoclay. A combined mechanical and ultrasonic mixing mode led to an extensive dispersion of silicate layers and thus the highest Young modulus in nanocomposites. The effect of clay content on tensile properties was also investigated. It was observed that the maximum stress strength would be attained for nanocomposite films with 6% (by weight) of clay loading. The chemical structure and morphology of the optimum sample was probed by FT-IR spectroscopy and transmission electron microscopy (TEM).