| 摘要 |
The present invention is a process for producing predominately four-armed asymmetric radial block copolymer which contain predominately, on average, two arms which are copolymers of at least one conjugated diene and at least one vinyl aromatic hydrocarbon and two conjugated giene homopolymer or copolymer arms, said process comprising: (a) anionically polymerizing at least one conjugated diene monomer and at least one vinylaromatic hydrocarbon monomer to form a set of living polymer arms, (b) anionically polymerizing at least one conjugated diene monomer to form another set of living polymer arms, (c) coupling the one set of living polimer arms with a coupling agent which is selected from the group consisting of tetramethoxysilane and (-glycidoxypropyltrimethoxysilane, (d) substantially completing the coupling reaction while leaving, on average, two unreacted coupling sites on the coupling agent, (e) adding the other set of living polymer arms to the product of d) and coupling the other set of living polymer arms to the first coupled set of polymer arms, and (f) optionally, hydrogenating the coupled polymer, either partially or fully.
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