【作者】 张颖；

【导师】 张可达；

【作者基本信息】 苏州大学 ， 应用化学， 2005， 硕士

【摘要】 本文由两部分组成:元素碘存在下的醋酸乙烯酯DT聚合;带有碘活性端基的聚醋酸乙烯酯与甲基丙烯酸甲酯的嵌段共聚。 本文首先对活性聚合、活性自由基聚合、DT聚合、醋酸乙烯酯DT聚合、醋酸乙烯酯的活性聚合、醋酸乙烯酯ATRP以及醋酸乙烯酯的嵌段聚合进行了文献调查,并加以总结和简短的评述。 1.元素碘存在下醋酸乙烯酯的DT聚合 发现在AIBN作为引发剂的醋酸乙烯酯自由基聚合体系中加入适量的元素碘,可使体系转化成DT聚合体系。元素碘量增加,诱导期变长,聚合速度变慢,分子量分布变窄,聚合反应的可控程度增加。 . 聚合动力学实验Ln[M₀]/[M]vs反应时间呈曲线,表明为非一级线性关系。分子量随时间线性增长,分子量分布M_w/M_n在1.3—1.5之间,说明该体系是典型的DT聚合。 核磁跟踪实验表明,AIBN和I₂在多种溶液或单体中可生成一种新物质α-碘代异丁腈,α-碘代异丁腈就是体系中起到链转移作用的碘化物。元素碘存在下醋酸乙烯酯的DT聚合的另一个特点是,在聚合条件下I₂与体系中含有的微量水,发生水解生成HI,HI与醋酸乙烯酯的双键发生加成生成乙酸α-碘代乙酯,该碘化物与碘为端基的聚醋酸乙烯酯一起成为链转移剂。 2.PVAc-I与甲基丙烯酸甲酯的嵌段共聚 分别采用DT及ATRP等两种方法,得到聚醋酸乙烯酯-b-甲基丙烯酸甲酯。PVAc-I作为大分子链转移剂,在AIBN作用下,与甲基丙烯酸甲酯发生共聚合。实际上该体系也可以认为是以PVAc-I链转移剂的甲基丙烯酸甲酯的DT聚合。所得的嵌段共聚物分子量分布较窄,GPC图和核磁结果表明嵌段共聚物的生成。PVAc-I用作ATRP引发剂,引发MMA聚合。PVAc-I可以分别与三种不同催化体系:CuCl/PMDETA,CuCl/MA₅-DETA和FeCl₂4H₂O/PPh₃实现ATRP。得到的嵌段物具有更多还原

【Abstract】 The thesis consists of two parts: 1. Degenerative transfer polymerization of vinyl acetate in the presence of iodine using AIBN as an initiator; 2.Synthesis of PVAc-b-PMMA block copolymersControlled/"Living" radical polymerization of vinyl acetate was achieved by a DT process with I₂ using AIBN as an initiator. After an induced period, the polymerization went smoothly. The conversion increases with the time and molecular weights of the polymers increase linearly with the conversions. The molecular weight distributions keep low （M_w/M_n<1.5）. ¹H NMR spectrum for the reaction solution of I₂ with AIBN, I₂ with VAc and the polymerization system of VAc/AIBN/ I₂ was measured respectively. The results indicated that I₂ reacted with AIBN to give the corresponding iodide （CH₃）₂（CN）C-I and I₂ reacted with VAc to give α - iodoethylacetate, which were both supposed to act as transfer agents. End-groups of the polyvinyl acetate were analyzed by ¹H NMR indicating that the iodo-terminated chain ends were unstable and decomposed to aldehyde groups.The copolymer of PVAc-b-MMA was synthesized with two methods. The first one employed PVAc bearing iodo-end groups as micro-transfer agent, in the presence of AIBN, methyl methacrylate was polymerized; In the second method, the polymerizationof MMA was conducted with PVAc -I as a macroinitiator catalyzed by CuCl/PMDETA, CuCl/MA₅-EDTA and FeCl₂·4H₂O/PPh₃.The polydispersities of the block copolymers were narrow. Also the molecular weights and structures of synthesized PVAc-b-MMA were characterized by GPC and ¹H NMR and shown that the block copolymers were novel.更多还原