Polypropylene–clay nanocomposites prepared by in situ grafting-intercalating in melt

Polypropylene–clay nanocomposites (PPCN) were prepared by in situ grafting-intercalating in melt. The organoclay was first modified with maleic anhydride (MA) in solution with a small quantity of a co-swelling agent and an initiator. It was then blended with PP in melt to obtain PP/clay grafting-intercalating composites (GIC). Finally, the GIC were blended with PP in melt to obtain PPCN. The nanostructure materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). The XRD patterns show that the basal distance in the MA-modified organoclay was 30 nm, which was larger than that of the original organoclay (19.6 nm). The XRD and TEM results for GIC and PPCN demonstrate that the layers of clay were partially exfoliated in the GIC and fully exfoliated in the PPCN. PPCN showed good thermal stability in the TGA analysis. The increased storage modulus indicates that the clay has a reinforcing effect in the PP matrix. The increased Tg of the PP/clay nanocomposites in dynamic mechanical analysis (DMA) implies that the PP macromolecules are intercalated or exfoliated between the interlayers of the silicate.