| 摘要 |
Rubbery polymers made by anionic polymerization can be coupled with tin halides or silicon halides to improve the characteristics of the rubber for use in some applications, such as tire treads. In cases where the rubbery polymer is synthesized by anionic polymerization utilizing a polar modifier it is difficult to attain a high level of coupling. This invention is based upon the unexpected finding that the coupling efficiency of rubbery polymers made with polar modifiers can be significantly improved by initiating the anionic polymerization with an alkylsilyloxy protected functional lithium initiator of the structural formula: wherein n represents an integer from 1 to 10, wherein R represents alkyl groups that can be the same or different, and wherein the alkyl groups contain from 1 to about 8 carbon atoms. The present invention more specifically discloses a process for synthesizing and coupling a rubbery polymer that comprises (1) polymerizing at least one conjugated diolefin monomer in the presence of a polar modifier to produce a living rubbery polymer, wherein said polymerization is an anionic polymerization that is initiated with an alkylsilyloxy protected functional lithium initiator of the structural formula: wherein n represents an integer from 1 to 10, wherein R represents alkyl groups that can be the same or different, and wherein the alkyl groups contain from 1 to about 8 carbon atoms, (2) reacting the living rubbery polymer with a coupling agent selected from the group consisting of tin halides and silicon halides.
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