Syndiotactic 1,2-polybutadiene is a thermoplastic resin which has double bonds attached in an alternating fashion to its polymeric backbone. Films, fibers and molded articles can be made utilizing syndiotactic 1,2-polybutadiene. It can also be blended into rubbers and cocured therewith. In such applications, sometimes it is beneficial for the syndiotactic 1,2-polybutadiene to have more than one melting point. This invention discloses a process for preparing syndiotactic 1,2-polybutadiene having at least two different melting points which comprises: polymerizing 1,3-butadiene monomer in an aqueous medium in the presence of (1) a catalyst composition which is made by reacting (a) at least one cobalt compound selected from the group consisting of (i) β-diketone complexes of cobalt, (ii) β-keto acid ester complexes of cobalt, (iii) cobalt salts of organic carboxylic acids having 6 to 15 carbon atoms and (iv) complexes of halogenated cobalt compounds of the formula CoXn, wherein X represents a halogen atom and n represents 2 or 3, with an organic compound selected from the group consisting of tertiary amine alcohols, tertiary phosphines, ketones and N,N-dialkylamides, (b) at least one organoaluminum compound of the formula AlR3, wherein R represents a hydrocarbon radical of 1 to 6 carbon atoms and (c) at least one conjugated diene; (2) at least one member selected from the group consisting of carbon disulfide, phenyl isothiocyanate and xanthic acid; and (3) at least one melting-point regulator and (4) a sodium halide salt or a potassium halide salt.
对位 1,2-聚
丁二烯是一种热塑性
树脂,其聚合物骨架以交替方式连接双键。利用对位 1,2-聚
丁二烯可制成薄膜、纤维和模塑制品。它还可以混入橡胶中并与之共混。在此类应用中,有时辛二聚
丁二烯具有一个以上的熔点是有益的。本发明公开了一种制备具有至少两个不同熔点的辛二聚
丁二烯的工艺,该工艺包括在
水介质中聚合
1,3-丁二烯单体,聚合过程中存在 (1) 催化剂组合物,该催化剂组合物是通过反应 (a) 至少一种
钴化合物制成的,该
钴化合物选自由以下组成的组 合:(i)
钴的
β-二酮络合物;(ii)
钴的β-
酮酸酯络合物;(iii) 具有 6 至 15 个碳原子的有机
羧酸的
钴盐;(iv) 式 CoXn 的卤代
钴化合物络合物、其中 X 代表卤素原子,n 代表 2 或 3,与选自由叔胺醇、叔膦、酮和 N,N-二烷基酰胺组成的组的有机化合物的络合物;(b) 至少一种式 AlR3 的
有机铝化合物,其中 R 代表 1 至 6 个碳原子的烃基;(c) 至少一种共轭二烯;(2) 至少一种选自
二硫化碳、异
硫氰酸苯酯和黄原酸的成员;以及 (3) 至少一种熔点调节剂和 (4) 卤化钠盐或卤化
钾盐。