| 摘要 |
<p>A catalyst composition for preparation of polymers of vinyl aromatic monomers having high syndiotacticity comprises (1) a cationic metal complex of the formula [CpmMXnX min p]<+>A<-> wherein: Cp is a single eta <5>-cyclopentadienyl group or a eta <5>-substituted cyclopentadienyl group; M is a metal of Group 4 of the Periodic Table; each X independently is an inert anionic ligand or a group of formula R, with the proviso that at least one X is R; X min is an inert, neutral donor ligand; each R independently is R min or hydride, wherein R min is hydrocarbyl, silyl or a mixture thereof, optionally substituted with one or more halogen atoms or alkoxy groups, and having up to 20 carbon and/or silicon atoms; m and p are independently 0 or 1; n is an integer greater than or equal to 1; and the sum of m and n is one less than the valence of M; and A<-> is a noncoordinating, compatible anion; and (2) an aluminum, magnesium or zinc metal hydrocarbyl in a metal complex : metal hydrocarbyl ratio of 1:1 to 1:1000; said components (1) and (2) being combined prior to contact with a vinyl aromatic monomer.</p> |
