Polypropylene/Organophilic clay Nanocomposites Using Metallocene Catalysts through in situ Polymerization

Автори: 
Monica de Oliveira and Maria de Fatima Marques

The organophilic clays employed for the preparation of supported metallocene catalysts Viscogel B8, Claytone HY and Cloisite 15A were evaluated in propylene polymerization. These supports were chemically pre-treated with trimethylaluminium (TMA). The organoclays, as well as the prepared metallocene catalysts, were analyzed by X-ray diffractometry (XRD). The polymers were also characterized by XRD, infrared absorption spectrometry (FTIR) for the determination of the isotactic index, by thermogravimetric analysis (TGA) for the determination of degradation temperatures, by differential scanning calorimetry (DSC) to determine thermal characteristics of the produced polypropylene, and by transmission electron microscopy (TEM) to examine the morphology of the materials obtained. All materials produced with the catalysts supported on organoclays showed higher melting and crystallization temperatures than the polypropylene (PP) obtained from the homogeneous catalyst as well as high dispersion of nanolayers of clays in PP matrix, although the catalyst activities of the supported system were much lower than the homogeneous one.

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