【作者】 包宏强；

【导师】 张可达；

【作者基本信息】 苏州大学 ， 应用化学， 2006， 硕士

【摘要】 首先对活性聚合、活性自由基聚合、原子转移自由基聚合(ATRP)、衰减链转移聚合(DT)、醋酸乙烯酯的活性聚合及其嵌段聚合进行了文献调查,并加以总结和简短的评述。实验主要有两部分组成:1.AIBN/Br2/DMF原位体系引发的原子转移自由基聚合(ATRP);2.制备醋酸乙烯酯的嵌段共聚物。首先用DT聚合体系来制备端基为碘的聚甲基丙烯酸甲脂(PMMA-I)和聚醋酸乙烯酯(PVAc-I),然后利用DT和ATRP方法进行交叉反应,即用四种方法来合成嵌段共聚物PMMA-b-PVAc和PVAc-b-PMMA。一.AIBN/Br2/DMF体系引发单体的ATRPAIBN和元素溴在溶剂DMF条件下可以原位生成α-溴代异丁腈,即(CH3)2(CN)C-Br,由于处于α位的-CN基团体积较小,同时具有强大的吸电子及共轭效应,由于电子的离域化,使C-Br键较弱,生成的异丁氰自由基较稳定,因而(CH3)2(CN)C-Br可能是ATRP的优秀引发剂。用本法原位合成的α-溴代异丁腈的DMF溶液,分别与CuCl/PMDETA、FeCl2/MA5-DETA和FeCl2/PPh3催化体系配合,引发MMA及St的原子转移自由基聚合。实验结果表明,聚合过程均呈现一级动力学特征且产物的分子量分布较窄(Mw/Mn=1.19-1.44), 1H NMR谱图显示在90℃下Br2和AIBN反应产生的烷基溴化物α-溴代异丁腈充当了引发剂。PMMA的端基分析显示聚合是由α-溴代异丁腈和催化体系氧化还原产生的异丁腈自由基引发的。发现当AIBN与元素溴等比例反应所得的引发体系中有残留的溴存在,溴存在一定的阻聚作用导致聚合前存在诱导期。而当AIBN与元素溴按照2:1反应时,聚合前没有诱导期,且聚合速度较前者快,分子量分布在1.4以下。本课题原位合成了一种新的,优秀的ATRP引发剂.与本实验室原位合成法合成的另一种ATRP引发剂α-碘代异丁腈相比稳定性更好,应用更普遍.更多还原

【Abstract】 The thesis consists of two parts: 1.Atom transfer radical polymerization (ATRP) of MMA and St initiated by AIBN/I2/DMF in situ system; 2.polyvinyl acetate terminated with iodine (PVAc-I) and iodo-terminated polymethyl methacrylate (PMMA-I) were as macro-transfer agents and macro-initiator, which were synthesized by degenerative transfer (DT) method in the presence of AIBN, then to prepare copolymers of PVAc-b-MMA and PMMA-b-VAc by DT and ATRP methods.1. The product of AIBN/Br2/DMF in situ system was as the initiator of the atom transfer radical polymerization to initiate methyl MMA and St. Three complexes: CuCl/PMDETA、FeCl2/MA5—DETA and FeCl2/PPh3 were as catalyst respectively. When the moles of AIBN and Br2 were same, remnant bromine existed in initiator system. So there was an induced period before polymerization. After induced period polymerization started. In all three catalyst system, the linear proportionality of the molecular weights to the conversions and straight lines observed in ln (M0/Mt) (where M0 and Mt are the symbols for monomer contents at the beginning and at any time, respectively) versus time plots indicated typical controlled living polymerization characteristics. The polydispersities of the polymer were narrow (MWDs were around 1.19-1.44). The results of analysis for terminate group of obtained polymer by 1H-NMR.2. DT method was applied to prepare iodo-terminated polymethyl methacrylate and polyvinyl acetate. Then they were used as macro-transfer agents and macro-initiate to synthesize copolymers in DT and ATRP methods. We found when PVAc-I was as macro-transfer agents, the polydispersities of the block copolymers were narrow and the molecular weight of copolymers was according with theory ones. On other hand, when PMMA-I was as macro-transfer agents, the resulted copolymers also had a narrow polydispersities but initiator efficiency was low. This is reasonable because更多还原