Supported metallocene catalysts are prepared with three key ingredients: silica support, aluminoxane activator (MAO), and metallocene pre-catalyst/catalysts. Ideally, the activated catalyst sites are uniformly distributed on the silica support in both inter- and intra-particle fashion. Non-uniform distribution of active sites on support often results in poorly controlled polymer particle growth pattern such as the generation of excess heat during initial stage of polymerization, quenching of active sites, and formation of fines and/or hollowed granules.<br/> <br/>Selected commercial and experimental silica supports have been characterized with PSD, BET, Hg-intrusion, SEM, and titration experiments with MAO activator. The distribution of MAO activator on silica support has been characterized with XPS and EDS/SEM. The distribution of MAO activator on silica supported catalyst system strongly depends on meso- and macro-pore size distributions, silica surface morphology, and various other factors such as calcination temperature and preparation method.

Impact of silica structure on the distribution of activator on supported catalyst particles

253rd National Meeting (2017)

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