A Facile Method for Preparation of Thermoplastic Starch/Urea Modified Montmorillonite Nanocomposites

A facile two-step melt extrusion processing method was used to prepare high performance thermoplastic starch (TPS)/urea modified montmorillonite (UMMT) nanocomposites in this work. X-ray diffraction (XRD) and transmission electron microscope (TEM) demonstrated that urea could destruct the multilayer and platelet structure of montmorillonite during the first melt extrusion processing, which was propitious to form intercalated or exfoliated nanocomposites in the second melt extrusion processing. UMMT, starch, and 30 wt% plasticizers (formamide and urea (1 : 2 wt%)) based on the starch could form partially exfoliated nanocomposites proved by XRD and TEM, respectively. Fourier transform infrared proved intense interactions existed in UMMT and TPS/UMMT nanocomposites. So high UMMT content could obviously increase the thermal stability and mechanical properties of nanocomposites, especially the tensile strength, Young’s modulus, and energy break could reach to 17.8 MPa, 210 MPa, and 760 J/m 3 , respectively. Finally, the increasing montmorillonite contents also decreased the water absorption and water vapor permeability of TPS material.