"EFFECT OF COCONUT OIL AND NANOCLAY ON PROCESSING AND PROPERTIES OF THERMOPLASTIC STARCH"
thermoplastic starch, coconut oil, montmorillonite clay, extrusion, polymeric nanocomposites
The aim of this work was to evaluate the effect of incorporating coconut oil (OC) and organophilic montmorillonite clay (OMMT) on the physical, chemical and mechanical properties of thermoplastic starch (TPS) obtained from cassava. The materials were mixed in a twin screw extruder and then processed in a single screw extruder with a flat ribbon matrix. The mixtures of TPS, OC, and OMMT produced easily processable materials with a good visual appearance. The results of the melt flow index (MFI) measurements showed that OC and OMMT promoted a reduction in the fluidity of the materials. Fourier transform infrared (FTIR) spectroscopy results showed the characteristic bands of the TPS, OC and OMMT structures. Colorimetric analysis showed a change in the color of materials with varying concentrations of OC and OMMT. The results of X-ray diffraction indicated the occurrence of clay exfoliation and the formation of polymeric nanocomposites of TPS. The mechanical behavior under tensile and Shore D hardness showed a sign of improvement in these properties with the addition of OC and OMMT. The water absorption test showed that the simultaneous addition of OC and OMMT in TPS reduced the hydrophilic character of polymeric nanocomposites. The results of the biodegradation test showed that the OC reduced the biodegradability process, while the OMMT accelerated the process. The polymeric nanocomposites obtained with TPS/OC indicated the potential for applications of new ecologically correct products developed on a large scale.