基于可见光引发的丙烯腈自由基聚合体系研究

发布时间：2018-07-12 15:32

本文选题：光聚合 + 聚丙烯腈　；参考：《江南大学》2017年硕士论文

【摘要】：本论文建立了两个新型的可见光引发聚合体系,实现了室温条件下丙烯腈的原子转移自由基聚合(ATRP)及无金属自由基聚合反应,获得了高分子量及窄分子量分布的聚丙烯腈(PAN),聚合过程操作简单,反应条件温和,低能耗,对环境友好。详细研究了聚合反应行为及可能的聚合机理。实验具体内容及结论如下:(1)室温可见光照射下以α-溴苄基乙酸乙酯(EBPA)为引发剂,在光氧化还原催化剂Ir(ppy)3作用下实现了丙烯腈(AN)的ATRP反应。考察了聚合体系的不同组分对实验结果的影响,并在Ir(ppy)3的催化作用下获得了高转化率、高分子量及窄分布的PAN(95%,Mn.MA LLS8.0×104 g/mol,Mw/Mn1.30)。探究Ir(ppy)3催化的聚合体系动力学行为,结果显示该体系的聚合行为具有典型的“活性”特征。此外,实验以制备的聚丙烯腈(PAN-Br)为大分子引发剂,与丙烯酸丁酯(BA)进行聚合合成了PAN-b-PBA嵌段共聚物。基于聚合行为及聚合产物的结构对该反应的机理进行了推测,推测该聚合机理为光引发的ATRP聚合。(2)室温可见光照射下以芳基四氟硼酸重氮盐为引发剂,在Eosin Y催化作用下实施AN无金属自由基聚合反应,考察了不同条件对聚合反应的影响,制得了高分子量及窄分子量分布的PAN(Mn,MALLS1.50×105 g/mol,Mn/Mw1.30)。实验在Eosin Y的催化体系下考察了AN的聚合行为,结果显示聚合行为表现出一阶线性动力学关系、聚合产物分子量随单体转换率的增大而增大,且分子量分布较窄(Mn/Mw1.30)。此外,通过调节LED灯光源的“开/关”状态可以调控聚合反应的发生与停止。采用基质辅助激光解吸电离-飞行时间质谱(MALDI-TOF MS)和19F NMR对聚合产物的结构进行分析,结果表明聚合反应是经捕获F-进行氧化终止的,但以合成的PAN-F为大分子引发剂,没能成功的实施扩链反应,表明该体系下制备的PAN分子链存在一定程度上的“死链”。通过对该体系聚合行为的分析及聚合产物的表征,表明该聚合体系的活化/失活过程类似于光引发的ATRP聚合机理。(3)室温可见光照射下以对氟苯基四氟硼酸重氮盐(1a)为引发剂,在Eosin Y催化作用下实施衣康酸((IA)、丙烯酸甲酯(MA)、丙烯酸丁酯(BA)、苯乙烯(St)、丙烯酰胺(AM)五种单体分别与AN的共聚反应,实验均获得了相应的共聚产物。对AN/IA和AN/MA两种共聚体系进行了进一步的研究,实验结果表明适量IA单体的加入不仅能提高聚合产物的分子量,制得高转化率、高分子量及窄分布的P(AN-co-IA)(Conv.90%,Mn,MALLS1.70×105 g/mol,Mn/Mw1.30),且能有效的缓解集中放热及在较低温度下引发环化反应。MA单体的加入对聚合产物分子量的影响不太,当AN与MA的摩尔比值在85:15时,差示扫描量热仪(DSC)曲线上丙烯腈聚合物在187℃左右会出现一个熔融峰,在分解温度(~315℃)之前。实验在AN/MA=85:15下考察了AN/MA的共聚行为,结果表明共聚行为呈现出一阶的线性动力学图,聚合物的分子量随分子量的增大而增大且保持分子量分布较窄(Mn/Mw1.30)。
[Abstract]:In this paper, two new visible light initiation polymerization systems have been established to achieve the atom transfer radical polymerization (ATRP) and free radical polymerization of acrylonitrile at room temperature. The polyacrylonitrile (PAN) with high molecular weight and narrow molecular weight distribution has been obtained. The polymerization process is simple, the reaction conditions are mild, the energy consumption is low, and the environment is friendly to the environment. The polymerization behavior and possible polymerization mechanism were studied in detail. The specific contents and conclusions were as follows: (1) the ATRP reaction of acrylonitrile (AN) was realized under the action of light oxidation-reduction catalyst Ir (PPy) (PPy) 3 under the visible light irradiation at room temperature. The experimental results of different components of the polymerization system were investigated. The high conversion, high molecular weight and narrow distribution of PAN (95%, Mn.MA LLS8.0 * 104 g/mol, Mw/Mn1.30) were obtained under the catalysis of Ir (PPy) 3. The kinetics of polymerization system of Ir (PPy) 3 catalyzed by Ir (PPy) 3 was investigated. The results showed that the polymerization behavior of the system had typical "activity" characteristics. In addition, the experiment was made of polyacrylonitrile (PAN-Br). PAN-b-PBA block copolymers were synthesized by polymerization of butyl acrylate (BA) for macromolecular initiator. Based on the polymerization behavior and the structure of the polymerization products, the mechanism of this reaction was speculated. It was deduced that the polymerization mechanism was light induced ATRP polymerization. (2) at room temperature visible light irradiation with aryl tetrafluoroboric acid diazonium as the initiator, Eosin Y Under the action of AN, the polymerization reaction of free radical polymerization was carried out. The effect of different conditions on the polymerization was investigated. The PAN (Mn, MALLS1.50 * 105 g/mol, Mn/Mw1.30) of the high molecular weight and narrow molecular weight distribution was prepared. The polymerization behavior of AN was investigated under the catalytic system of Eosin Y. The results showed that the polymerization behavior showed the first order linear dynamics. The molecular weight of the polymerization products increases with the increase of the monomer conversion rate, and the molecular weight distribution is narrow (Mn/Mw1.30). In addition, the polymerization reaction can be regulated by adjusting the "open / close" state of the LED lamp light source. The structure of the polymerization products by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and 19F NMR The results showed that the polymerization was stopped by the capture of F-, but the synthesized PAN-F was a large molecular initiator, and the chain reaction was not successfully carried out. It showed that there was a certain "dead chain" in the PAN molecular chain prepared under the system. The activation / inactivation process of the polymerization system is similar to the photopolymerization mechanism of light induced ATRP. (3) under the room temperature visible light irradiation with fluoro phenyl tetrafluorboric acid diazonium (1a) as initiator, under the catalysis of Eosin Y, itaconic acid (IA), methyl acrylate (MA), butyl acrylate (BA), styrene (St), and acrylamide (AM) of the five monomers are in common with AN, respectively. The copolymerization products were obtained by the polymerization. The two copolymerization systems of AN/IA and AN/MA were further studied. The experimental results showed that the addition of appropriate IA monomers could not only improve the molecular weight of the polymerization products, produce high conversion rate, high molecular weight and narrow distribution of P (AN-co-IA) (Conv.90%, Mn, MALLS1.70 * 105 g/mol, Mn/Mw1.30). It can effectively alleviate the concentration of heat and the reaction of.MA monomer at lower temperature. The effect of the addition of.MA monomer on the molecular weight of the polymerization products is not very. When the molar ratio of AN to MA is at 85:15, the acrylonitrile polymer on the differential scanning calorimeter (DSC) curve will appear a melting peak at about 187 C, before the decomposition temperature (~315 C). The experiment is in AN. The copolymerization behavior of AN/MA was investigated under /MA=85:15. The results showed that the copolymerization behavior showed a first order linear kinetic diagram. The molecular weight of the polymer increased with the increase of molecular weight and kept the molecular weight distribution narrower (Mn/Mw1.30).
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631.5

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