| 主权项 |
1. A process to produce polyethylene comprising:
(a) contacting ethylene with a supported metallocene catalyst system;
wherein the supported catalyst system comprises:(i) a support material;(ii) an alumoxane activator having from about 1 wt % to about 14 wt % trimethylaluminum, based on the weight of the alumoxane activator;(iii) a metallocene compound represented by the formula: whereinT is Si or Ge;each RA is a C1 to C20 substituted or unsubstituted hydrocarbyl group;each RB is, independently, H or a C1 to C8 substituted or unsubstituted hydrocarbyl group, or a group represented by the formula —CH2Rx;wherein Rx is a C1 to C20 substituted or unsubstituted hydrocarbyl group provided that at least one RB is methyl or a group represented by the formula —CH2Rx;each RC is, independently, H or a C1 to C20 substituted or unsubstituted hydrocarbyl group;each A is independently selected from the group consisting of C1 to C20 substituted or unsubstituted hydrocarbyl groups, hydrides, amides, amines, alkoxides, sulfides, phosphides, halides, dienes, phosphines, and ethers, and two A groups can form a cyclic structure including aromatic, partially saturated, or saturated cyclic or fused ring system;each X is, independently, hydrogen, halogen or a substituted or unsubstituted C1 to C20 hydrocarbyl, and two X groups can form a cyclic structure including aromatic, partially saturated, or saturated cyclic or fused ring system;further provided that any of adjacent RA, RB, and/or RC groups may form a fused ring or multicenter fused ring systems, where the rings may be substituted or unsubstituted, and may be aromatic, partially unsaturated, or unsaturated; (b) obtaining a vinyl terminated polyethylene having:
(i) at least 60% allyl chain ends, based on total unsaturations;(ii) a molecular weight distribution of less than or equal to 4.0;(iii) an Mn (1HNMR) of at least 20,000 g/mol; and(iv) wherein the polyethylene is an ethylene polymer having less than 2wt % of a C3 to C40 alphaolefin comonomer. |
