METHOD FOR PREPARING A DILITHIUM INITIATOR AND ANIONIC POLYMERISATION METHOD

摘要

The invention concerns a method for preparing a dilithium initiator for use in anionic polymerisation, a method for preparing by anionic polymerisation a living diene elastomer provided with a carbon-lithium group at each of its chain ends, and a method for preparing a three-block copolymer from said living diene elastomer. The inventive method for preparing a dilithium initiator consists in reacting in an aliphatic or alicylic hydrocarbon solvent a first reagent consisting of a dialkenyl benzene and a second reagent consisting of secondary butyl lithium, so that the ratio of the number of moles of the first reagent over the number of moles of the second reagent is substantially equal to 0.5, and said method is characterised in that it consists in causing said reagents to react in the presence of a diamine, so that the resulting initiator essentially consists of a double adduct resulting from the addition of a secondary butyl lithium on each of the double bonds borne by said dialkenyl benzene.