| 摘要 |
Three-block copolymers of the ABA and ABC type are disclosed in which A and C are plastomeric monomers and B is an elastomeric polymer are disclosed, which are prepared by first polymerizing the block A in such a way to keep alive the active centers in the chain ends for a time sufficient to permit the addition of the second monomer B, whereafter, with the aid of a special catalytic system, the growth of the third block C, can be carried out. A and C are mutually interchangeable. The catalyst for polymerizing the block A is a Lewis' acid aided by isobutene and the catalyst for introducing and copolymerizing C (or A) is a chloride of aluminium alkyl.
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