PROCESS FOR THE PREPARATION OF DIENE POLYMERS OR RANDOM VINYL ARENE-DIENE COPOLYMERS

Process for the preparation of a diene polymer or a random vinyl arene-diene copolymer comprising anionically (co)polymerising at least one conjugated diene monomer, optionally in the presence of at least one vinyl arene, in the presence of at least one hydrocarbon solvent, at least one lithium-based initiator and at least one organic compound containing at least one nitroxide group having general formula (I) or (II): wherein: R1, R2, R3 and R4, mutually identical or different, represent a hydrogen atom; or are selected from C1-C20, preferably C1-C8, linear or branched alkyl groups optionally containing heteroatoms such as, for example, oxygen, nitrogen,sulphur,optionally substituted cycloalkyl groups, optionally substituted C1-C20, preferably C1-C8 , linear or branched alkoxy groups, optionally substituted aryl groups; -x is an integer ranging from 0 to 7, preferably ranging from 4 to 5; -y is an integer ranging from 1 to 3, preferably ranging from 1 to 2.