| 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.
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