PROCESS FOR PREPARING BIMODAL OR MULTIMODAL POLYMERS OF CONJUGATED DIENES

摘要

A process of preparing a bimodal or multimodal homopolymer of a conjugated diene or a bimodal or multimodal copolymer of a conjugated diene with another conjugated diene or with a vinyl aromatic compound consists in polymerizing the monomer(s) in a reaction medium at a temperature of between 20.degree.C. and 200.degree.C. in the presence of a catalyst system formed of the reaction product of: (a) an organic compound of a metal of group 3A of the periodic classification of elements of the Mendeleev Table having one of the following formulas: M1M3R1R2R3R4 M2(M3R1R2R3R4)2 M3R1R2R3 M1OM3R1R2 with (b) at least one electron-donor compound containing at least one heteroatom, and adding hydrogen as a modifying agent to the reaction medium during the course of the polymerization reaction.