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vinyyliaromaattisen monomer and konjugoituneen dieenin between stellar lohkosekspolymeeri, its production method and this sekapolymeeria and crystalline polystyrene cover compositions
vinyyliaromaattisen monomer and konjugoituneen dieenin between stellar lohkosekspolymeeri, its production method and this sekapolymeeria and crystalline polystyrene cover compositions
Star-shaped block copolymer of general formula [S1-S2-(B1/S3)-B2]m-X-[B2-(B1/S3)-S2 ]n in which X denotes a polyfunctional radical originating from a coupling agent, m and n denote nonzero integers such that m + n is equal to 3 or 4, each of S1 and S2 denotes a block of a polymer of at least one vinylaromatic monomer, B2 denotes a block of a polymer of at least one conjugated diene, (B1/S3) denotes a block of a statistical copolymer of at least one vinylaromatic monomer and of at least one conjugated diene, 40 to 75 % by weight of (B1/S3) consisting of units originating from vinylaromatic monomer, characterised in that the block B2 contains more than 40 % by weight and less than 90 % by weight of all conjugated diene present in the said star-shaped block copolymer. The invention also relates to the process for obtaining this copolymer. The compositions including this copolymer and crystal polystyrene exhibit remarkable mechanical properties and transparency.
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