| 摘要 |
<p>The invention especially relates to a method for producing a functionalised, coupled or star-shaped block copolymer which can be used in a rubber composition that can be cross-linked with sulphur and has reduced hysteresis in the cross-linked state, at least one of the blocks consisting of a polyisoprene and at least one other block consisting of a diene elastomer other than a polyisoprene, the molar rate of units from one conjugated diene or a plurality thereof being higher than 15 %. The inventive method comprises the following steps: (i) at least one monomer comprising a conjugated diene other than isoprene is copolymerised by means of a catalytic system comprising a hydrocarbonated solvent, a compound A of a metal from the group IIIA, a compound B of an alkaline earth metal and a polymer initiator C comprising a linkage C-Li consisting of a monolithiated polyisoprene used to form the polyisoprene, the polyisoprene block(s) having a molecular mass Mn1 of between 2500 and 20000 g/mol, such that the block(s) other than a polyisoprene have a 1,4-trans chain content equal to or higher than 70 % and a molecular mass Mn2 of between 65000 and 350000 g/mol; and (ii) a functionalising, coupling, or star-shaping agent respectively comprising one, two or three epoxy groups is added to the copolymerisation product, so that the block other than a polyisoprene is functionalised, coupled or star-shaped.</p> |
