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/MgCl₂/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 microscale. Transmission electron microscopy (TEM) photographs showed that the MMT homogeneously dispersed in the PE.