Thermoplastic starch-clay nanocomposites and their characteristics

In the quest for improved performance from polymers that offer biodegradation and therefore environmental acceptability, one approach is the addition of natural clays to produce nanocomposites. This study examines nanocomposites of glycerol-plasticized starch, with untreated montmorillonite and hectorite. Treated hectorite and kaolinite were added to produce conventional composites within the same clay volume fraction range for comparison. X-ray diffraction and transmission electron microscopy are used to confirm the type of composite. The ultrasonic pulse-echo technique was used to measure Young's and shear modulus. The nanocomposites presented greater increases in modulus for a given volume fraction of clay thus contributing to this new class of biodegradable and environmentally acceptable materials, although the results indicate that a plasticizer other than glycerol is preferable. (C) 2005 Elsevier Ltd. All rights reserved.