Abstract: The invention relates to a block diene elastomer corresponding to the following formula: where: n and m are each an integer of greater than or equal to 0, such that n+m?1 and n+m?20, each A block is composed of a polybutadiene, each B block is composed of a diene elastomer, the molar content of units resulting from conjugated dienes of which is greater than 15%, the B blocks being identical to one another, X is an organic or inorganic group which can comprise a functional group which interacts with a reinforcing filler, the number-average molecular weight Mn1 of each A block varies from 2 500 to 20 000 g/mol, the number-average molecular weight Mn2 of each B block varies from 80 000 to 350 000 g/mol, and the content of 1,2-linkages in each A block is between 1 and 20%.

Abstract: The invention relates to a functionalized diene elastomer composed a) of a specific block copolymer functionalized, at the chain end or in the middle of the chain, by a tin functional group, b) of a specific block copolymer star-branched by tin and c) of a content of less than 15% by weight, with respect to the total weight of the functionalized diene elastomer, of a specific non-tin-functional block copolymer.

Abstract: The invention relates to a functionalized diene elastomer composed: a) of a diene elastomer functionalized, at the chain end or in the middle of the chain, by a tin functional group, exhibiting a monomodal distribution of molecular weights before functionalization and a polydispersity index before functionalization of less than or equal to 1.3, b) of a diene elastomer star-branched with a tin compound, exhibiting a monomodal distribution of molecular weights before star-branching and a polydispersity index before star-branching of less than or equal to 1.3, and c) of a content of less than 15% by weight, with respect to the total weight of the functionalized diene elastomer, of a non-tin-functional diene elastomer, the said diene elastomers a), b) and c) being, before optional functionalization or optional star-branching, the same in nature.

Abstract: The present invention relates to a novel initiating system for the preparation of a living diene elastomer functionalized at the chain end by an amine group by anionic polymerization. The novel initiating system comprises an organolithium compound and a tin amide. The invention also relates to processes for the preparation of modified elastomers comprising an amine group at the chain end. These modified elastomers prove to be particularly advantageous in reinforced rubber compositions for tyres as they confer improved dynamic and mechanical properties in the vulcanized state.

Abstract: The present invention relates to a monomodal coupled diene elastomer having a silanol functional group in the middle of the chain, to its process of preparation and to a rubber composition which can be used in particular in the manufacture of tire covers, having improved hysteresis and physical properties in the vulcanized state and an improved processing in the raw state, comprising a monomodal diene polymer having a silanol functional group in the middle of the chain and a reinforcing inorganic filler. The process for obtaining this elastomer having a silanol functional group in the middle of the chain comprises a reaction of the diene monomer(s) and of the polymerization initiator in the presence of a chelating polar agent, a reaction of the living diene polymer with a coupling agent and then, after hydrolysis, a recovery of the coupled diene polymer having a functional group in the middle of the chain.

Abstract: The present invention relates to a specific functionalized diene elastomer. This functionalized elastomer exhibits a reduced cold flow without, however, damaging the properties of a reinforced rubber composition in which it is present, in particular the processing properties and the hysteresis properties. This functionalized diene elastomer carries, at the chain end, a silanol functional group or a polysiloxane block having a silanol end and is partially coupled by or star-branched by tin.

Abstract: The present invention relates to a novel initiating system for the preparation of a living diene elastomer functionalized at the chain end by an amine group by anionic polymerization. The novel initiating system comprises an organolithium compound and a tin amide. The invention also relates to processes for the preparation of modified elastomers comprising an amine group at the chain end. These modified elastomers prove to be particularly advantageous in reinforced rubber compositions for tyres as they confer improved dynamic and mechanical properties in the vulcanized state.

Abstract: The present invention relates to a monomodal coupled diene elastomer having a silanol functional group in the middle of the chain, to its process of preparation and to a rubber composition which can be used in particular in the manufacture of tyre covers, having improved hysteresis and physical properties in the vulcanized state and an improved processing in the raw state, comprising a monomodal diene polymer having a silanol functional group in the middle of the chain and a reinforcing inorganic filler. The process for obtaining this elastomer having a silanol functional group in the middle of the chain comprises a reaction of the diene monomer(s) and of the polymerization initiator in the presence of a chelating polar agent, a reaction of the living diene polymer with a coupling agent and then, after hydrolysis, a recovery of the coupled diene polymer having a functional group in the middle of the chain.

Abstract: A polymerization process for styrene derivatives in which a styrene monomer is placed in contact with a catalyst system in a solvent, including at least: