process for the production of crystalline vinylaromatischen polymers with mainly syndiotaktischer structure

摘要

Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing the vinylaromatic monomers in the presence of a catalytic system consisting essentially of: a) a complex of titanium having the formula (I): Ti(OCONRR')n wherein R and R', the same or different, represent a C1-C12 aliphatic radical or C6-C12 aromatic radical whereas n is an integer equal to 3 or 4; b) a cocatalyst selected from aluminoxane and a compound of boron having formula (II): BX1X2X3 wherein X1, X2 and X3, the same or different, represent a C1-C20 perfluorinated hydrocarbon radical.