Process for preparation of syndiotactic vinyl aromatic polymers.

摘要

A process for preparing syndiotactic vinyl aromatic polymers comprising contacting one or more aromatic monomers under polymerization conditions with a catalyst corresponding to the formula: [CpmMXnX min p]<+>A<-> wherein: Cp is a single eta <5>-cyclopentadienyl or eta <5>-substituted cyclopentadienyl group; M is a metal of Group 3, 4, 5, 6, 8, 9, 10 or the Lanthanide Series of the Periodic Table; X each occurrence is an inert anionic lignd, with the proviso that at least one X is R; X min is an inert, neutral, donor ligand; R is hydrocarbyl, silyl, a combination thereof or a substituted derivative thereof having up to 20 carbon, silicon or carbon and silicon atoms; m and p are independently 0 or 1; n is an integer greater than or equal to 1; the sum of m and n is equal to the valence of M; and A<-> is a noncoordinating, compatible anion of a Bronsted acid salt.