Propylene polymerization with modified Ziegler-Natta catalysts

The effect of stereochemistry and polydispersity on nanocomposite properties has yet to be explored fully. An intriguing result was obtained by Quijada et al. who performed melf mixing of PP-g-MA with octadecylamine-modified montmorillonite or hectorite, then blended these materials with different isotactic polypropylenes. Nanocomposites with better clay exfoliation were obtained using metallocene polypropylene compared to Ziegler-Natta polypropylene, presumably because of ifs lower polydispersity. While stereoselective metallocene catalysts have been used successfully for in situ propylene polymerization in combination with clay supports (see Section 5.2.2.2), the materials properties of these nanocomposites have thus far received insufficienf affention. 

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