Using inorganic POSS-modified laponite clay to support a nickel α-diimine catalyst for in situ formation of high performance polyethylene nanocomposites

A new strategy was developed for in situ formation of polyethylene nanocomposites, in which synthetic laponite clay was first modified by octaaminopropyl polyhedral oligometric silsesquioxane (OapPOSS) and then used to support a nickel α-diimine late-transition-metal catalyst for ethylene polymerization. The resulting polyethylene nanocomposites were investigated with respect to their structure and properties by x-ray diffraction analysis (XRD), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). It was found that the layered silicates could be exfoliated effectively in the polyethylene matrix. In comparison with pure polyethylene, the polyethylene in the nanocomposites has a lower branching degree. The combination of OapPOSS with the laponite clay particles results in a remarkable increase in storage modulus and thermal decomposition temperature.