CIPRIANO, Pâmela Bento.; CANEDO, Eduardo Luis.; CARVALHO, Laura Hecker de.
Resumo:
In this work the effects of processing conditions (screw profile, temperature profile and extrusion speed) on
the mechanical properties of PP/organobentonite nanocomposites processed by single srew extrusion were
ascertained. Two screws with different profiles wee used to process the samples: 1) a standard screw (RC)
and 2) a specially designed screw with mixing elements (RE). Nanocomposites with nominal 1% w/w clay
content were single screw extruded and the effective clay content present in the nanocomposites was
determined by calcination. The systems were tensile and impact tested and characterized by optical
microscopy and X-ray diffraction (XRD).The data did not show significant improvements in nanocomposite
mechanical properties, indicating the need for a compatibilizing agent. Calcination evinced that the amount
of clay effectively incorporated into the systems was smaller than the nominal amount added. Optical
microscopy revealed that better clay dispersion was achieved in the systems processed with the special
screw (RE). X-ray diffraction indicated that irrespective of processing temperature profile (180 or 240°C)
adopted, intercalated structures were achieved only with the samples processed using the RE screw
operating at high shear rates (120rpm). Conventional microcomposites were obtained with all other
processing conditions adopted (low shear rates and conventional (RC)single screw extrusion).