Simultaneous Polypropylene Functionalization and Nanoclay Dispersion in PP/Clay Nanocomposites using Ultrasound

Polypropylene nanocomposite materials were prepared with 5 and 10 wt % cloisite C20A clay, jointly with 0.6 and 1.2 wt % of maleic anhydride (MA) for the simultaneous polymer functionalization and clay dispersion in a twin screw extruder assisted with ultrasonic irradiation, using different sonication intensities (231, 347, and 462 W, which correspond to 30%, 45%, and 60% of the maximum instrument intensity, 770 W) all in a single-step operation. The MA polymer functionalization was followed by FTIR spectroscopy and determined by titration. The increase in modulus of the obtained PP/Clay nanocomposites was attributed to the greater dispersion level, presumably achieved becuase of the joint application of the PP-Clay compatibilization with MA and the sonication during processing in a twin screw extruder. The greater level of clay dispersion was verified by the displacement of the XRD diffraction peak to lower angles, indicating an intercalated-exfoliated structure that was corroborated by STEM. (c) 2014 Wiley Periodicals, Inc.