稀土催化剂催化丁烯-1/1,3-丁二烯高顺式共聚合制备新型橡胶

Introduction of 1-butylene unit into cis-1,4-polybutadiene via copolymerization of 1-butylene coming from byproducts of petroleum coal chemical industry and 1,3-butadiene can lead to novel high-value rubber materials. Because of huge differences in the reactivities of two monomers, cis-1,4 selective copolymerizations of 1,3-butadiene and 1-butylene are highly challenging projects to date. In this project, novel half-sandwich rare-earth metal complexes are designed and synthesized by tuning Lewis acid of the metal center and ligand steric effect to realize copolymerizations of 1-butylene with 1,3-butadiene. The influences of catalyst structure on the polymerization activity, cis-1,4 regioselectivity, and reaction ratios of two monomers are investigated in detail. The influences of polymerization conditions on the incorporation of 1-butylene and sequence distribution of copolymer are also studied in detail. Random copolymers of 1-butylene and 1,3-butadiene are prepared on the optimal conditions with cis-1,4 selectivity, which can be applied as novel high-performance rubbers. Furthermore, the influence of the growing chain end group on the insertion of next monomer is elucidated by means of DFT calculation, which is helpful for deep insight into copolymerizaiton mechanism of two monomers.

利用石油化工和煤化工的副产物丁烯-1与1,3-丁二烯顺1,4-选择性共聚合可以制备得到性能优良的新型橡胶材料。然而由于丁烯-1和1,3-丁二烯两类单体反应性差别大，丁烯-1和1,3-丁二烯高顺1,4-选择性共聚，是具有挑战性的课题。本项目拟设计新型杂环稠合单茂基稀土配合物，通过调节中心金属的Lewis酸性和空间效应，实现丁烯-1与1,3-丁二烯高选择性共聚。探索催化剂结构对聚合活性、1,3-丁二烯顺1,4-选择性与单体间竞聚率的影响。研究聚合反应条件对丁烯-1插入率、序列长度及分布、分子量及分布的影响规律，最终获得高顺1,4-结构、不同序列分布的丁烯-1/丁二烯新型橡胶。借助理论计算揭示链末端基团对下一单体插入的影响，从本质上揭示两种单体共聚机理。

由于α-烯烃和共轭二烯两类单体聚合机理和反应性差别大，所以α-烯烃和功能化α-烯烃与1,3-丁二烯高选择性共聚，是具有挑战性的课题。我们利用新型限制几何构型单茂基稀土配合物和杂环稠合单茂稀土配合物，通过调节中心金属的Lewis酸性和空间效应，进行了含硫原子极性α-烯烃单体和丁二烯共聚合、乙烯与2,3-二甲基丁二烯共聚合、丁烯-1和丁二烯共聚合研究。实现了丁二烯顺1,4选择性与4-甲硫基-1-丁烯（MTB）)、对甲苯硫基-1-丁烯（pTTB）的共聚合，发现硫原子配位能力的强弱在共聚物序列分布、组成和选择性上起重要作用。配位能力较强的MTB与BD共聚时，由于极性基团的配位优先，MTB消耗完BD才能插入到聚合物链中，得到两嵌段共聚物。然而，配位能力弱的对甲苯硫基-1-丁烯，得到pTTB插入率任意调节、无规序列分布的共聚物。通过乙烯与DMBD共聚合得到2,3-二甲基丁二烯单元为1,2-选择性并具有良好的拉伸强度和高断裂伸长率的新型橡胶材料；丁烯-1与丁二烯共聚中，通过调控茂环上取代基和两种单体的投料比，得到了丁烯-1插入率为18 mol%共聚物。系统研究了催化剂结构对聚合活性、1,3-丁二烯和极性a-烯烃选择性、a-烯烃插入率、序列长度及分布、分子量及分布的影响规律。借助DFT理论计算揭示链末端基团对下一单体插入的影响，从本质上揭示两种单体共聚机理。