| 摘要 |
Novel block copolymers comprise units derived from conjugated diere(s) (D), aromatic vinyl cpd(s). (A) and alpha-defin(s) (M) and are represented by formula (I). - (A)a(D)b(M)c (I) - The copolymers are characterised in that:- a=20-5000; b = 1-10; M = propylene, c = degree of polymn and is such that the polypropylene block has an Mn of 10000-200000and the polypropylene block comprises a mixt. of isotactic, heterotactic and syndiotactic triads, pref. in the following resp. amts.:-30-60%, 20-35% and 20-35%. - Also claimed is the prodn. of block copolymers. The aromatic vinyl cpd. comprises styrene, x-methyl styrene, vinyl naphthalene and/or vinyl toluene. The conjugated diene comprises 1,3-butadiene; isoprene; poperylene; 2,3-dimethyl-1,3-butadiene; 2,3-dimethyl 3-butadiene and/or 1-phenyl-1,3-butadiene. GBAB- GB2156368 B Block copolymers comprising units derived from at least one conjugated diene D, units derived from at least one vinyl-aromatic compound A, and units derived from at least one alpha-olefin M, the structure of the block copolymer being represented by the formula (A)a(D)b(M)c, wherein: a is greater than or equal to 20 and less than or equal to 5000; b is greater than or equal to 1 and less than or equal to 10; M is propylene, the degree c of copolymerisation of propylene is such that the average molecular weight of the polypropylene block is from 10,000 to 200,000 and the polypropylene block consists of a mixture of isotactic, heterotactic and syndiotactic triads.
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