Study of polypropylene/montmorillonite nanocomposites prepared by solid-state shear compounding (S3C) using pan-mill equipment:: the morphology of montmorillonite and thermal properties of the nanocomposites

In this paper, polypropylene (PP)/organophilic montmorillonite (OMMT) nanocomposites were successfully prepared without any compatibilizers by solid-state shear compounding ((SC)-C-3) using panmill equipment. X-ray diffraction (XRD) patterns show that the OMMT characteristic (001) peak at 2theta equal to 4.59 degrees disappeared for the milled OMMT and corresponding composites. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) photographs show that the thickness of pan-milled OMMT decreased from ca 100-200 nm to ca 30-50 nm, and OMMT was partly exfoliated in the PP matrix because the pan-type mill can exert fairly strong squeezing force in the normal direction and shearing force in both radial and tangential directions on milled materials. PP/OMMT nanocomposites at low OMMT loading have higher melting point, crystallization temperature, thermal degradation temperature and heat distortion temperature than those of neat PP. Moreover, addition of OMMT accelerates crystallization of PP significantly. (SC)-C-3 is a novel approach to prepare polymer/layered silicate nanocomposites with high performances at low filler loading. (C) 2004 Society of Chemical Industry.