Synthesls and Characterization of Block Copolymers consisting of Conjugated Monomers and Ethylene by Means of Active Site Modification

通过对嵌段共聚物活性位修饰的合成与表征研究，得到以下结果。首先，通过活性聚苯乙烯的活性位改性，合成了窄分子量分布的苯乙烯-乙烯嵌段共聚物。类似地，由异戊二烯和乙烯链段组成的嵌段共聚物已经通过“活性位点改性”的方式合成，所述“活性位点改性”通过向用烷基锂引发的活性聚合物中添加适当的叔二胺如N，N，N，N-四甲基乙二胺（TMEDA）和鹰爪豆碱来进行。所形成的嵌段共聚物具有相对窄的分子量分布，并且在IP链段的微观结构中保留了主要的1，4-结构单元。在不存在叔二胺的情况下，不能允许与乙烯的这种嵌段共聚，并且仅回收异戊二烯的均聚物。采用二苯乙烯对乙烯和甲基丙烯酸甲酯进行链端改性，合成了烷基锂与叔二胺配合物的嵌段共聚物。这些应用于乙烯和异戊二烯的均聚。用~ 13 CNMR和GPC研究了TMEDAN络合的烷基锂引发乙烯聚合<13>。在仲丁基锂和叔丁基锂的情况下，引发和终止链端均由13 <13>C NMR谱确定，并且聚合物的GPC洗脱曲线随反应时间向高分子量侧移动。这表明烷基锂中烷基引发的乙烯聚合和增长物种具有活性。在异戊二烯的情况下，聚合物的微观结构可以通过活性中心改性来控制。

The following results were obtained from the study on synthesis and characterization of block copolymers by means of active site modification. First, block copolymer consisting of styrene and ethylene bearing narrow molecular weight distribution has been synthesized by means of active site modification performed by the addition of t-diamines to living poly(styrene). Similarly, block copolymer consisting of isoprene and ethylene segments has been synthesized by means of "active site modification" performed by adding appropriate t-diamines such as N,N,N,N-tetramethylethylenediamine (TMEDA) and sparteine to the living polymer initiated with alkyllithium. Block copolymers formed have a relative narrow molecular weight distribution and retained the mainly 1,4-units in the microstructure of IP segment. Such block copolymerization with ethylene could not be admitted in the absence of the t-diamines and only homopolymer of isoprene was recovered. Block copolymer of ethylene and methyl methacrylate with alkyllithium complexed with tert-diamines by means of chain end modification by diphenyl ethylene was synthesized. These were applied to homopolymerization of ethylene and isoprene. The polymerization of ethylene initiated with alkyllithiums complexed by TMEDAN was studied by using ^<13>C NMR spectroscopy and GPC. In the cases of s-butyllithium and t-butyllithium, both initiation and termination chain end were determined by ^<13>C NMR spectra, and GPC elution curves of the polymers shifted to higher molecular weight side with reaction time. This suggests that the polymerization of ethylene initiated with alkylgroups in alkyllithiums and propagating species have a living nature. In the case of isoprene, the microstructure of the polymers could be controlled by the activesite modification.