甲基丙烯酸甲酯的高效ATRP催化体系研究

作ቤተ መጻሕፍቲ ባይዱ
者：郭
婷
指导老师：程振平 教授
II
Study on Highly Efficient Catalytic System for ATRP of Methyl Methacrylate
Abstract
Study on Highly Efficient Catalytic System for ATRP of Methyl Methacrylate Abstract
硕士学位论文
论文题目 甲基丙烯酸甲酯的高效 ATRP 催化体系研究 研究生姓名 指导教师姓名 专 业 名 称 研 究 方 向 论文提交日期 郭 婷
程振平 高分子化学与物理 活性自由基聚合 2013 年 3 月
甲基丙烯酸甲酯的高效 ATRP 催化体系研究
中文摘要
甲基丙烯酸甲酯的高效 ATRP 催化体系研究 中文摘要
In this thesis, two kinds of highly efficient catalytic systems for atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) were established, namely iron-mediated activators generated by electron transfer (AGET) ATRP in the presence of catalytic amounts of sodium hydroxide and ppm concentration of organocopper-mediated initiators for continuous activator regeneration (ICAR) ATRP. In the former system, the polymerization rate was improved via adding sodium hydroxide (NaOH) to reduce the value of iron redox potential, which reflects the catalytic ability in iron-mediated ATRP. In the latter one, by employing oil-soluble organocopper as the catalyst, the concentration of catalyst was decreased to less than 2 ppm and meanwhile the polymerization rate still kept fast and its controllability on molecular weight and molecular weight distribution remained well (Mw/Mn＜1.23). The thesis can be summarized as follows: (1) System I: Catalytic amounts of NaOH were added to the system of iron-mediated AGET ATRP of MMA for improving the polymerization rate and finally obtained a highly efficient catalyst system. In this system, ethyl 2-bromoisobutyrate (EBiB) acted as the initiator, oxidative FeCl3· 6H2O as the catalyst, tris-(3,6-dioxa-heptyl) amine (TDA-1) as the ligand, glucose as the reducing agent and tetrahydrofuran (THF) as the solvent. After adding NaOH in this system, the polymerization rate can be increased significantly while keeping good controllability over molecular weight and molecular weight distribution. Besides, the effect of the concentration of Fe(III) on the polymerization was also investigated in this work. The chain end of the PMMA was analyzed by 1H NMR spectroscopy and successful chain extension proved the livingness of the obtained PMMA. At the last, cyclic voltammetry (CV) of catalyst complex with/without NaOH were
1
H NMR, UV-vis spectroscopy and
chain-extension experiments were carried out to prove the livingness of the obtained
Written by Ting Guo Supervised by Prof. Zhenping Cheng
I
中文摘要
甲基丙烯酸甲酯的高效 ATRP 催化体系研究
核磁(1H NMR)和紫外可见光谱(UV-vis)表征以及以聚合物 PMMA 为大分子引发剂进 行的扩链反应，证明了聚合物的“活性”特征并提出了聚合反应机理。 关键词：AGET ATRP，铁盐催化剂，碱性添加剂，ICAR ATRP，有机铜盐催化 剂，ppm 级催化剂用量， “活性”自由基聚合
IV
目
第一章
录
文献综述 ........................................................................................................... 1
1.1 引 言 .................................................................................................................. 1 1.2 原子转移自由基聚合(ATRP) ............................................................................. 2 1.2.1 ATRP 原理概述 .......................................................................................... 2 1.2.2 传统原子转移自由基聚合(ATRP) ............................................................ 2 1.2.3 电子转移生成催化剂的 ATRP (AGET ATRP) .......................................... 3 1.2.4 铁盐催化的电子转移生成催化剂的 ATRP (Iron-mediated AGET ATRP) 4 1.2.5 电子转移再生催化剂的 ATRP(ARGET ATRP) ........................................ 6 1.2.6 引发剂持续再生催化剂的原子转移自由基聚合(ICAR ATRP) ................ 7 1.2.7 原子转移自由基聚合中的添加剂............................................................. 9 1.2.8 以假卤素为转移原子的 ATRP ................................................................. 9 第二章 第三章 论文目的和意义 ............................................................................................. 13 实验部分 ......................................................................................................... 15
本论文建立了 2 个甲基丙烯酸甲酯的高效 ATRP 催化体系。 首先研究了用葡萄糖 为还原剂的 Fe(III)催化甲基丙烯酸甲酯(MMA)的 AGET ATRP 体系， 通过在体系中加 入无机碱 NaOH，降低铁盐的氧化还原电位，从而获得高效的催化体系。另一方面， 采用油溶性有机铜盐催化 MMA 聚合， 成功构建新型的高效的 ICAR ATRP 催化体系， 使体系中催化剂用量降至 ppm 级并保持较快的聚合速率以及较好的控制性。主要的 研究内容和结果如下： (1) 体系一：将催化剂量的 NaOH 加入到铁盐催化的 AGET ATRP 体系中，通 过提高铁盐的氧化还原能力提高聚合速率，从而获得活性较高的催化体系。聚合体系 以甲基丙烯酸甲酯(MMA)为单体，2-溴代异丁酸乙酯(EBiB)为引发剂，FeCl3·6H2O 为催化剂，三-(3,6-二氧杂庚基)胺(TDA-1)为配体，葡萄糖(PTT)为还原剂，四氢呋喃 (THF)为溶剂的条件下，详细研究了在加入与不加无机碱 NaOH 的条件下 MMA 聚合 动力学，研究发现加入 NaOH 后，聚合速率明显加快同时对聚合控制性影响不大；同 时也考察了在碱性条件下 Fe(III) 浓度对聚合反应的影响。通过对聚合物的核磁(1H NMR)表征以及以聚合物为大分子引发剂进行扩链反应，表明聚合所得的 PMMA 具 有 “活性” 链末端。 最后通过对加入与不加 NaOH 时三价铁络合物进行循环伏安表征， 证实了加入碱性物质能够加快聚合速率的机理的推测。 (2) 体系二：采用油溶性有机金属铜盐做催化剂，AIBN 为自由基引发剂的均相 ICAR ATRP 体系，首次在兼顾聚合速度和聚合控制性的情况下将催化剂用量降至 2ppm 以下。聚合体系以 MMA 为单体，以 1,4-(2-溴-2-异丁酰氧)苯(BMPB2)为 ATRP 引发剂，N,N-二丁基二硫代氨基甲酸铜(Cu(SC(S)N(C4H9)2)2)或 N,N-二丁基二硒代氨 基 甲 酸 铜 (Cu(SeC(Se)N(C4H9)2)2) 为 催 化 剂 ， N,N,N',N',N''- 五 甲 基 二 亚 乙 基 三 胺 (PMDETA)为配体，详细研究了催化剂以及自由基引发剂浓度对聚合体系的影响以及 其动力学特征， 结果表明聚合都呈现一级动力学关系，聚合物的分子量随着转化率的 增加而增加并和理论分子量相吻合，且聚合物分子量分布较窄(Mw/Mn＜1.23)。通过
III
中文摘要
甲基丙烯酸甲酯的高效 ATRP 催化体系研究
investigated to further study the polymerization mechanism. (2) System II: A new ICAR ATRP system using organocopper as the catalyst and azobis (isobutyronitrile) (AIBN) as free radical initiator was successfully studied. In this system, the amount of catalyst was firstly decreased to less than 2 ppm while keeping higher polymerization rate and better controllability over the polymerization. In this ICAR ATRP system, two organocopper species Cu(SC(S)N(C4H9)2)2 or Cu(SeC(Se)N(C4H9)2)2 were used as the catalyst, 1,4-(2-bromo-2-methylpropionato) benzene (BMPB2) as the ATRP initiator and N,N,N′,N′′,N′′-pentamethyl-diethylenetriamine (PMDETA) as the ligand. The effect of catalyst concentration and free radical initiator concentration was studied in detail. The polymerization showed the first-order polymerization kinetics, and the resultant molecular weights corresponding to their theoretical ones increased linearly respect to monomer conversion while keeping low molecular weight distributions (Mw/Mn＜1.23). The resultant polymers were analyzed by PMMA and infer the polymerization mechanism. Keywords: AGET ATRP, iron catalyst, basic additives, ICAR ATRP, organocopper catalyst, ppm level catalyst, living radical polymerization