BLOCK CO-POLYMER STARRED WITH AN AROMATIC VINYL MONOMER AND A CONJUGUATED DIENE, PRODUCTION PROCESS OF THE SAID CO-POLYMER AND COMPOSITIONS INCLUDING IT AND CRYSTAL POLYSTYRENE

摘要

the invention relates to a copolymer block of general formula u00a2s1 star s2 - s3 b1 / b2). m - x - u00a2b2 (b1 / s3 - s2. n in which x is a radical derived from a poly functional coupling agent.m and n are integers greater than zero as m + n is equal to 3 or 4, s1 and s2, each representing a block of a polymer of at least one vinylaromatique monomer.b is a polymer block of a conjugated diene and at least one (b1 / s3) is a block copolymer of a monomer of at least one vinylaromatique statistics and at least one conjugated diene40 to 75% by weight of (b1 / s3) consisting of monomer units derived from vinylaromatique.characterized in that the block b2 contains more than 40% by weight and less than 90% by weight of the total copolymer block of conjugated diene content in the dark.the invention also relates to the process for the production of the copolymer and the composition comprising the copolymer and polystyrene.such compositions exhibit excellent mechanical properties and transparency.