BACKGROUND: Both exfoliated and toughened polypropylene‐blend‐montmorillonite (PP/MMT) nanocomposites were prepared by melt extrusion in a twin‐screw extruder. Special attention was paid to the enhancement of clay exfoliation and toughness properties of PP by the introduction of a rubber in the form of compatibilizer toughener: ethylene propylene diene‐based rubber grafted with maleic anhydride (EPDM‐g‐MA). RESULTS: The resultant nanocomposites were characterized using X‐ray diffraction, atomic force microscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis and Izod impact testing methods. It was found that the desired exfoliated nanocomposite structure could be achieved for all compatibilizer to organoclay ratios as well as clay loadings. Moreover, a mechanism involving a decreased size of rubber domains surrounded with nanolayers as well as exfoliation of the nanolayers in the PP matrix was found to be responsible for a dramatic increase in impact resistance of the nanocomposites. CONCLUSION: Improved thermal and dynamic mechanical properties of the resultant nanocomposites promise to open the way for highly toughened super PPs via nanocomposite assemblies even with very low degrees of loading. Copyright © 2008 Society of Chemical Industry

Highly toughened super high-impact polystyrene (HIPS)/organophilic montmorillonite (Org-MMT) nanocomposite was prepared by solution blending method. Organophilic modification of MMT layered silicate was achieved by using a special toughener-intercalant, quaternary ammonium salt of -tertiary amine functionalized polybutadiene and shown by X-ray diffraction analysis. The resulting HIPS/Org-MMT nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and static and dynamic mechanical analyses. The morphological study of HIPS/Org-MMT nanocomposite showed that nanolayers were exfoliated in nanocomposite and moreover caused much more well dispersed and reduced PS occluded rubber domains. This mechanism was found to be responsible for dramatic increase in toughness of nanocomposites. Additionally, improved thermal and dynamic mechanical properties of the resultant nanocomposite promises to open a new way for highly toughened super HIPSs via nanocomposite assemblies even with a very low degree of clay loading.

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