| 摘要 |
The present invention relates to block copolymers intended to constitute an elastomeric matrix of a cross-linkable rubber composition with reduced hysteresis, to such a rubber composition which is usable in the cross-linked state in a tire tread, to such a tire tread and to a tire comprising said tire tread which exhibits reduced rolling resistance. A copolymer with n blocks (n=2 or 3) according to the invention, each of said blocks comprising a diene elastomer having a molar content of units originating from conjugated dienes of greater than 15%, and one or each of said blocks which forms the chain end of said copolymer consisting of a polyisoprene, when n=2 or n=3 respectively, is such that the number-average molecular weight Mn1 of said or each polyisoprene end block is between about 2,500 and 20,000 g/mol, and such that the number-average molecular weight Mn2 of the block of said copolymer which is other than said or each polyisoprene end block is between about 80,000 g/mol and 350,000 g/mol.
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