Structural and optical properties of polypropylene–montmorillonite nanocomposites

In this work, polypropylene–commercial montmorillonite organophilic clay nanocomposites were prepared using a Werner Pfleiderer twin-screw extruder. Considering the nonpolar characteristic of the polypropylene, polypropylene-graft-maleic anhydride (PP-g-MA) was used as a coupling agent to improve the intercalation process into the layers of montmorillonite. The materials containing 2.5, 5.0, 7.5 and 10.0% of the clay (N2.5, N5, N7.5 and N10) and PP and two extra compositions containing only PP and 15.0 and 30.0% of PP-g-MA (PP, P15 and P30), respectively, were investigated upon the nanocomposites structures. The properties of materials were characterized by X-ray diffraction (XRD), SEM analysis and reflectance spectrophotometry. The X-ray diffraction showed exfoliated or intercalated structure for different concentrations; the SEM analysis showed a good dispersion of the clay in the PP matrix and the spectrophotometric analysis showed that the amount of clay used in the compositions resulted in different levels of opacity.