PROCESS FOR THE PRODUCTION OF VINYLAROMATIC POLYMERS WITH A HIGH DEGREE OF SYNDIOTACTICITY

摘要

Process for the preparation of crystalline vinylaromatic polymers with a high degree of syndiotacticity which comprises polymerizing vinylaromatic monomers in the presence of a catalytic system essentially consisting of: a) a complex of titanium selected from those having the general formula: (CpR1R2R3R4R5)TiX3 (I) wherein the groups R1, R2, R3, R4 and R5 represent a hydrogen atom or C1-C10 alkyl groups; X represents a hydrogen atom, a halogen such as chlorine, a C1-C10 alkyl or oxyalkyl radical or a C6-C12 oxyaryl radical; b) an alkylaluminoxane; and c) an organic derivative of tin; characterized in that the alkylaluminoxane is methyl-aluminoxane (MAO) treated at 20-80.degree.C under vacuum for 1-100 hours and the organic derivative of tin is tin tetraphenyl.