Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure

摘要

Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing vinylaromatic monomers, alone or mixed with at least one other monomer, in the presence of a catalytic system essentially consisting of: a) a complex of titanium or zirconium selected from those having general formula:MR1R2R3R4, A1MR1R2R3, A1A2MR1R2(I) b) a co-catalyst selected from an alkylalumoxane and a compound of boron having formula (II):BX1X2X3(II) or one of its salts; c) a derivative of tin having general formula:SnR5R6R7R8(III)