【作者】 周弟；

【导师】 朱秀林；

【作者基本信息】 苏州大学 ， 高分子化学与物理， 2008， 博士

【摘要】 二硫代氨基甲酸酯类化合物是有机含硫化合物中比较重要的一类,目前,这类化合物在“活性”/可控自由基聚合领域得到了广泛应用,如作为苯乙烯等单体聚合的iniferter试剂,原子转移自由基聚合（ATRP）中作为引发剂,以及作为可逆加成-断裂链转移（RAFT）聚合的链转移试剂。这些“活性”/可控自由基聚合集自由基聚合（free radical polymerization）与活性聚合（living polymerization）的优点于一体,既可像自由基聚合那样进行本体、溶液、悬浮和乳液聚合,又可合成具有指定结构和分子量的聚合物,因此具有十分广阔的应用前景,引起了很多高分子化学研究者的关注。其中,RAFT技术是当今“活性”/可控自由基聚合最为活跃的研究方向之一。在RAFT聚合中,二硫代氨基甲酸酯是多种单体聚合的有效链转移试剂,文献报道较早的是二硫代吡咯甲酸酯和二硫代咪唑甲酸酯。本论文合成了16个不同结构的新型二硫代氨基甲酸酯,经核磁,元素分析,液相色谱等方法确定了结构,得到了3个二硫代氨基甲酸酯的单晶,测试了单晶结构的键长键角数据,对含芳香环的二硫代氨基甲酸酯的荧光性能进行了测试。同时,系统研究了不同Z基团结构（Z1^Z9）和R基团结构（R1^R8）的二硫代氨基甲酸酯对苯乙烯、丙烯酸酯类,甲基丙烯酸酯类单体的聚合控制性能,探索了选择和设计二硫代氨基甲酸酯结构与聚合控制性能的规律。通过考察二硫代氨基甲酸酯Z基团结构对苯乙烯聚合的影响发现:4,5-二苯基咪唑（Z1）,1,2,4-三氮唑（Z2）,吲哚（Z4）,2-苯基吲哚（Z5）,2-苯基苯并咪唑（Z6）和咔唑（Z7）为Z基团的二硫代氨基甲酸苄酯对苯乙烯的聚合具有很好的可控性,表现为“活性”/可控自由基聚合特征;取代二氢吡啶（Z3）、10-氢吩噻嗪（Z7）和二苯并哌嗪（Z9）为Z基团的二硫代氨基甲酸苄酯对苯乙烯的聚合不具有可控性;以Z2为RAFT试剂的苯乙烯聚合速率比Z1为RAFT试剂的聚合速率快,Z2对于苯乙烯RAFT聚合不存在阻滞现象;相同实验条件下,Z5对苯乙烯RAFT聚合的可控性要好于Z4,并且随着聚合温度提高,Z4催化苯乙烯热引发聚合速度明显加快,但对于苯乙烯RAFT聚合存在阻滞现象。通过考察二硫代氨基甲酸酯R基团结构（苄基系列:苄基（R1）、萘苄（R2）、对乙烯基苄基（R3）;酯基系列:α-异丙酸乙酯基（R4）、α-异丁酸乙酯基（R5）、α-苯乙酸甲酯基（R6）、α-环丁内酯基（R7）和α-异丁酸偶氮苯酯基（R8））对乙烯基单体聚合的影响发现:R2较R1对苯乙烯和丙烯酸甲酯的RAFT聚合具有更好的可控性;以R3为RAFT试剂可以非常方便的进行聚合物分子设计,可以一步法制备超支化结构聚合物,并且转化率越高,支化程度越大;相同实验条件下,对于苯乙烯聚合速率按如下顺序递减:R5 > R2 > R6 > R1,聚合可控制性按如下顺序降低:R2,R5 R7 > R1 > R4;除R4外,这些二硫代咔唑甲酸酯对丙烯酸甲酯的聚合也具有非常好的可控性;但实验条件下,这些二硫代咔唑甲酸酯对于甲基丙烯酸甲酯不是有效的RAFT试剂,只有当R基团中引入大共轭基团偶氮苯时（R8）,甲基丙烯酸甲酯的聚合才具有一定可控性。以上所得到的分子量可控和分子量分布窄的聚合物经核磁共振、红外、紫外等谱图表征结构和扩链反应验证聚合物活性,结果均说明二硫代氨基甲酸酯碎片已经成功接入聚合链端。根据RAFT聚合机理,可以方便地进行聚合物分子设计,通过对RAFT试剂Z基团和R基团的设计,可以方便地制备端基功能化、嵌段、梳状、星型、超支化等特殊结构聚合物。本论文将芳香环吲哚、苯基取代吲哚、咔唑、萘环等基团通过RAFT聚合引入聚合物链端,系统研究了芳香环封端聚合物的稳态和瞬态荧光性能。结果发现:相同测试条件下,这些芳香环封端聚合物的荧光性能较其对应小分子二硫代氨基甲酸酯强,并随聚合物分子量的增大而增强;聚合物的荧光寿命都在纳秒级别,以Z5和R4封端的聚合物的荧光寿命不随聚合物分子量的增长而变化,而以Z4封端的聚合物的荧光寿命随聚合物分子量的增长而变长,提供了一种研究不同分子量端基标记聚合物吸收图谱、发射图谱和荧光寿命的简便方法。同时,还利用由RAFT方法得到的端基含唑基团的聚合物与金属、金属离子配位,制备得到聚合物/金属复合材料。结果发现:含唑基团封端聚合物在溶剂N, N-二甲基甲酰胺（DMF）与稀土金属离子进行自组装,形成的聚合物/稀土金属复合材料具有非常优异的荧光性能,并且与小分子稀土金属配位化合物的荧光性能存在明显差异;在超声辐照下通过还原硝酸银（AgNO₃）,原位制备了规则的核/壳结构聚苯乙烯包覆纳米银粒子（AgNPs）,反应速率快,由RAFT聚合制备的端基含唑基团聚合物是有效的纳米银粒子稳定剂。RAFT聚合还有显著的优点,即单体适用面十分广泛,几乎包括了所有适用于自由基聚合的单体。本文由RAFT聚合方式制备了侧链含1-（2-吡啶偶氮）-2-萘酚（PAN）结构的共聚物,聚合具有“活性”/可控自由基聚合特征,所得聚合物分子量可控,分子量分布窄;经核磁和元素分析对共聚物组成进行了分析;由配位化学方法制备了与过渡金属离子Cu （II）和稀土金属离子Eu （III）的配位共聚物,并对其结构进行了红外和紫外-可见光谱表征。用简便的方法考察了聚合物分子量大小对配位能力的影响;并系统研究了配位共聚物的荧光性能和热性能,结果发现:Eu （III）配位共聚物有强荧光吸收和发射,而Cu （II）配位共聚物不具有荧光,但聚合物与Cu （II）配位后玻璃化温度提高,Eu （III）配位共聚物在170℃左右发生热分解。更多还原

【Abstract】 Dithiocarbamates are a sort of most important sulfocompounds and widely used as the catalyst in“living”/controlled radical polymerization, such as iniferter, ATRP and RAFT polymerization.“Living”/controlled radical polymerization bonds the advantages of radical polymerization and living polymerization. It can be carried out in bulk, solvent, suspension and latex systems, and widely used in the synthesis of novel structure, controlled molecular weight (Mn) and low molecular weight distribution (Mw/Mn) polymers. Therefore, it catches the interests of researchers in polymer science for it’s widely foreground. Among the“living”/controlled radical polymerization methods, the RAFT polymerization come to front and gets the most attention now.In RAFT process, dithiocarbamates are effective chain transfer agents for the polymerizations of a series of monomers. The early reported structures of dithiocarbamates were benzyl 1H-pyrrole-1-carbodithioate and benzyl 1H-imidazole-1-carbodithioate. In this thesis, sixteen dithiocarbamates with different structures (labeled as Z1~Z9 and R1~R8) were synthesized and characterized by NMR, EA and HPLC. The parameters of three single crystals (Z5, Z8 and R7) were measured also. Furthermore, the fluorescence properties of dithiocarbamates were studied in detail. The influences of chemical structure of these dithiocarbamates with different Z (Z1-Z9) or R (R1-R8) groups on the RAFT polymerizations of styrene, acrylates, and methyl acrylates were investigated. The polymerizations of styrene with AIBN initiation or thermal initiation were performed in the presence of dithiocarbamates with different N-groups, i.e., benzyl 4,5-diphenyl-1H-imidazole-1-carbodithioate (Z1), benzyl 1H-1,2,4-triazole-1-carbodithioate (Z2), dimethyl 4-(2-nitrophenyl)-1-((1-phenylethylthio)carbo- nothioyl)-1,4-dihydropyridine-3,5-dicarboxylate (Z3), benzyl indole-1-carbodithioate (Z4), benzyl 2-phenyl-indole-1-carbodithioate (Z5), benzyl 2-phenyl-1H-benzo[d]imidazole-1-carbodithioate (Z6), benzyl phenothiazine-10-carbodithioate (Z7), benzyl 9H-carbazole-9-carbodithioate (Z8), and benzyl dibenzo[b,f]azepine-5-carbodithioate (Z9). The resultes show that the structure of N-group of dithiocarbamate has significant effects on the activity of dithiocarbamates in the polymerization of styrene. Z1, Z2, Z4, Z5, Z6, and Z8 are effective RAFT agents for the polymerization of styrene. The polymerizations showed good living characteristics. However, in the cases of Z3, Z7 and Z9, the obtained polymers showed uncontrolled molecular weights and broad molecular weight distributions. The results showed that Z5 is more effective than Z4, and the phenyl substitution group of phenyl on this dithiocarbamate has obvious effects on effectiveness of controlled polymerization of styrene. The polymerization rate is markedly influenced by the conjugation structure of the N-group of dithiocarbamate, and the polymerization rate of Z2 is greater than Z1. For Z2, the rate of polymerization seems independent of the RAFT agent concentration. However, a significant retardation in the rate of polymerization is observed in the case of Z4. For the influences of chemical structures of dithiocarbamates with different R groups on the RAFT polymerizations, carbazole-9-carbodithioic acid benzyl ester (R1), carbazole-9-carbodithioic acid naphthalen-1-ylmethyl ester (R2), 4-vinylbenzyl 9H-carbazole-9-carbodithioate (R3), ethyl 2-(9H-carbazole-9-carbonothioylthio)propanoate (R4), 2-(carbazole-9- carbothioylsulfanyl)-2-methyl-propionic acid ethyl ester (R5), (carbazole-9- carbothioylsulfanyl)-phenyl-acetic acid methyl ester (R6), 2-oxo-tetrahydrofuran-3-yl 9H-carbazole-9-carbodithioate (R7), and 2-(phenylazo-phenyl-carbonyl) prop-2-yl 9H-carbazole-9-carbodithioate (R8) were synthesized and used to the RAFT polymerizations of styrene , methyl methacrylates (MMA, BMA) and methyl acrylates (MA, BA, OA) respectively. The results showed that these dithiocarbamates were effective RAFT agents for the polymerizations of styrene. The polymerizations were well-controlled with the characteristics of“living”/controlled polymerization and the polymerization rate of styrene with thermal initiation was markedly influenced by the chemical structures of the group R in dithiocarbamates, and decreased in the order of R5>R2>R6>R1. For the polymerization of MA, the efficiency of RAFT agents was in the following order: R2, R5~ R7>R1>R4, and R4 was not an effective RAFT agent for the MA polymerization. The synthesized dithiocarbamates can not control the polymerization of MMA except by introducing azo benzene structure into the R group (R8).Based on the RAFT polymerization mechanism, it is conveniently to prepare expectant end-labelled polymer with designed structures (controlled molecular weight and low molecular weight distribution) by designing proper Z and R groups and the end functionality of obtained polymer should be high. In this thesis, aromatic groups (carbazole, 2-phenyl-indole, indole and naphthalene) end-labelled polystyrenes (PS) were prepared conveniently via RAFT polymerization using dithiocarbamates Z4, Z5, R2 and R4 as RAFT agents. The steady-state and the time-resolved fluorescence techniques had been used to study the fluorescence behavior of obtained end-labelled PS. The results showed that these aromatic end-labelled PS exhibited structured absorptions and emissions. The fluorescence intensity of polymers is stronger than those of dithiocarbamates and increase with the polymer’s molecular weights..The fluorescence lifetimes of Z5 and R4 resulting PS had no obvious change with different molecular weights. The lifetimes of Z4 resulting PS increased with molecular weights. The measured fluorescence lifetimes were in the range of nanosecond in all case. Furthermore, RAFT polymerization was also used to prepare polymer/metal composites with coordination chemistry: By self-assembly technique, Z2 and Z5 resulting end-functional PS coordinated with rare earth metal in N, N-dimethylformamide (DMF) to generate the fluorescent Eu-PS and Sm-PS complexes; Z2 and Z5 resulting PS coated spherical silver nanoparticles (AgNPs) with well core/shell structure were conveniently prepared in situ by reducing Ag~+ to Ag~0 under ultrasound irradiation in the presence of DMF and H2O.Functional monomers can be polymerized by RAFT polymerization. In this thesis, a novel monomer containing pyridylazo-2-naphthoxyl group, 1-(1-(4-vinylbenzyloxy) naphthalen-2-yl)-2-(pyridin-2-yl)diazene (VBNPA), was successfully synthesized and copolymerized with styrene (St) in DMF via RAFT polymerization using 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as RAFT agent. The polymerization behavior exhibited“living”/controlled characters. The obtained copolymer, poly(St-co-VBNPA), with pre-determinable molecular weight and narrow molecular weight distribution can be used as a carrier in metal ion detection and analysis via pre-concentration technique. The copolymer-metal ion (copper (Cu) and europium (Eu)) complexes were prepared and the optical and thermal properties were characterized.更多还原