中文摘要：

通过向十二烷基苯磺酸（DBSA）/环己烷溶液中滴加正丁基锂（n-Bu Li）的方法原位制备n-Bu Li/十二烷基苯磺酸锂（LDBS）引发体系,研究了该体系引发苯乙烯负离子聚合行为,并采用GPC、NMR、UV、SEM、LPS和TG等手段对苯乙烯聚合物进行表征。结果表明,该引发体系以络合体、聚集体等多种形态存在;苯乙烯在这种特殊微化学环境中的产物由不溶性和可溶性聚合物两部分组成,聚苯乙烯与LDBS紧密包裹形成不溶性微粒聚合物,可溶性聚苯乙烯等规立构三元组的个数分数为41%,等规五元组个数分数为21%;LDBS的浓度和比例增大,引发活性降低,聚合反应转化率降低,分子量分布加宽;利用低活性的PSLi/LDBS体系可在室温下引发甲基丙烯酸甲酯聚合。

英文摘要：

The anionic polymerization of styrene in cyclohexane initiated by n-butyl lithium/ lithium dodecylbenzenesulfonate（ n-Bu Li/ LDBS） has been investigated. The initiator system was prepared through an in situ method of dropping n-butyllithium into dodecylbenzenesulfonic acid（ DBSA）/ cyclohexane solution. The polystyrene was characterized by means of gel permeation chromatography（ GPC）,NMR,UV,SEM,LPS,and TG. The results revealed that the n-Bu Li/ LDBS initiating system existed in form of either a complex or aggregate,depending on the concentration. When the n-Bu Li/ LDBS concentration was relatively low,n-Bu Li/ LDBS formed a complex state which regulated the polymerization behavior. However,when the concentration of n-Bu Li/ LDBS was relatively high,n-Bu Li/ LDBS formed an aggregated state which influenced the polymer morphology. Compared with classical anionic polymerization system,some new features appeared with this unique chemical microenvironment of the active center,namely polystyrene was composed of soluble and insoluble sections,and the isotactic triad content in the soluble section was 41%,while the isotactic pentad content reached 21%. The formation of insoluble sections can be attributed to the high degree of isotacticity and the fact that LDBS was tightly bound to polystyrene. The molecular weight of the soluble section,measured by GPC,reached million grade. With increasing concentration of LDBS and cLDBS/ cn-Bu Liratio,the activity of the initiator and polymerization conversion both decreased,and the molecular weight distribution of the polystyrene broadened. Owing to the low initiating activity of PSLi/ n-Bu Li,the polymerization of methyl methacrylate at room temperature was possible.