| 摘要 |
The process and catalyst system of this invention can be utilized to synthesize polybutadiene rubber having a high trans content and a low melting point by solution polymerization. The trans-polybutadiene rubber made by the process of this invention can be utilized in tire tread rubbers that exhibit outstanding wear characteristics. More importantly, the trans-polybutadiene rubber of this invention can be easily processed because of its low level of crystallinity. In fact, the trans-polybutadiene made by the process of this invention does not need to be heated in a "hot-house" before being used in making rubber compounds. This invention more specifically reveals a process for synthesizing trans-polybutadiene rubber which comprises polymerizing 1,3-butadiene in an organic solvent in the presence of a catalyst system which comprises (a) an organolithium compound, (b) a barium compound selected from the group consisting of (i) barium salts of cyclic alcohols, such as barium mentholate, and (ii) barium thymolate, and (c) an organoaluminum compound. The trans-polybutadiene made with the catalyst system of this invention typically has a glass transition temperature that is within the range of about -97° C. to about -90° C., a melting point that is within the range of about -30° C. to about 30° C., and a number average molecular weight that is within the range of about 50,000 to about 400,000.
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