Structural and thermal stabilization of isotactic polypropylene/organo-montmorillonite/poly(ethylene-co-octene) nanocomposites by an elastomer component

Rheological and thermal properties of isotactic polypropylene (iPP)/organo-montmorillonite (OMMT)/poly(ethylene-co-octene) (PEOc) ternary nanocomposites and iPP/OMMT binary nanocomposites were studied by X-ray diffraction (XRD), rheometry, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) in this paper. The clay layers were mainly intercalated and partially exfoliated and well dispersed in these nanocomposites with the help of maleic anhydride modified polypropylene (PPgMA). Clay layers were mainly localized close to/inside the PEOc-rich phase from the direct observation of morphological study. A compact and stable network structure was formed in ternary composites when clay content was 2 phr (parts per hundred parts of iPP/PPgMA) or higher, which resulted in the lower stress relaxation rate and a pseudo-solid like behavior in low frequency region. Compared with iPP/OMMT composites, iPP/OMMT/PEOc composites had a much stronger ability to resist thermal decomposition. In another word, combining with the filler network, PEOc greatly improved the structural and thermal stabilities of iPP/OMMT nanocomposites.