Preparation and morphology of polyethylene/clay nanocomposite with novel MgCl2/montmorillonite (MMT) bi-supported Ziegler-Natta catalyst.

In the present article, the spherical and high activity TiCl4/MgCI2/MMT intercalated catalyst was successfully prepared. The active centers of obtained catalyst well dispersed in the MMT through electron probe micro-analysis (EPMA). The d-spacing of MMT was broadened from 0.97 nm to 1.42 nm after addition of MgCl2 and the space between MMT layers was 1.60 nm after treated with excess TiCl4. In addition, the catalyst shows a very high activity toward ethylene polymerization. During the ethylene polymerization, the MMT layers were exfoliated by the polymerization force arising from the propagation of ethylene chain. Interestingly, the macro-scale morphology of the obtained polyethylene (PE)/MMT nanocomposite still retained the spherical shape of precursor catalyst; while the PE particles contain MMT platelets take the shape of "flower petal" in the micro-scale. Transmission electron microscopy (TEM) photographs showed that the MMT homogeneously dispersed in the PE.