UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    Ethylene Polymerization Using a Zirconium Amidinate Supported Catalyst
    (2004-05-07) Young, Andrea Elise; Sita, Lawrence; Chemistry
    A series of W. R. Grace Davison IOLA(TM), methylaluminoxane-silica (MAO/Silica) and MAO/IOLA support materials were used to activate and immobilize a zirconium amidinate single site catalyst of the formula Cp*ZrMe2[tBuNC(Me)NCEt]. Ethylene homo-polymerizations and co-polymerizations with 1-hexene were conducted in heptane and compared. The catalysts activity was investigated under varying condition such as pre-catalyst loading, pressure, temperature, co-monomer incorporation and additives. The catalyst supported on the MAO/IOLA B support material proved to be more active than the IOLA and m-IOLA support activators, and the MAO/Silica and MAO/IOLA A support materials. A difference in activity of as much as 1015 gPE/gcat.h-1 was noted. The catalyst sensitivity to varying ethylene polymerization conditions such as temperature and pressure were investigated for the MAO/IOLA B supported catalyst. Catalyst activities of more than 2100 gPE/gcat.h-1 were achieved. Homo-polymer and co-polymer samples were characterized and compared with respect to their melting temperature, molecular weights and polydispersities.