Compounding of nanocomposites by thermokinetic mixing

摘要

Nanocomposites have been prepared by melt mixing poly(propylene) (PP) and different levels of a premixed montmorillonite-organoclay masterbatch (PP/ clay concentrate). Melt mixing was achieved using a Gelimat, a high-speed thermokinetic mixer. The Gelimat system is designed to handle difficult compounding and dispersion applications and can achieve mixing, heating, and compounding of products within a minute. Therefore, the thermal history of the compounded polymer is short, which limits degradation. The structure and properties of the nanocomposites prepared with a Gelimat were compared to ones prepared with a twin-screw extruder. The structure and properties of PP/clay nanocomposites were compared by TEM, X-ray diffraction, mechanical testing, and rheological analysis. Results indicate that a better dispersion of the clay can be achieved by thermokinetic mixing when compared to extrusion, resulting in better mechanical properties. Calculations, based on simplifying assumptions, showed that the shear rates generated in a Gelimat are at least one order higher than those generally generated in an extruder. (c) 2005 Wiley Periodicals, Inc.