Synthesis Of Poly[2-(n,n-dimethylamino)ethyl Methacrylate]-b-poly(acrylamide-azobenzene)Block Copolymer And Research On The Properties Of Its Micelle

In this thesis,poly[2-(N,N-dimethylamino)ethyl methacrylate]-b-poly-(acrylamide-azobenzene)(PDMAEMA-b-PAAAB)block copolymers and micelle solution were synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization,using 2-(N,N-dimethylamino)ethyl methacrylate(DMAEMA)and acrylamido-azobenzene(AAAB)as monomers,2-cyanoprop-2-yl dithiobenzoate(CPDB)as a chain transfer agent.The structures and performances of these polymers were characterized and determined,then the properties of micelle solution were investigated.1.The chain transfer agent CPDB was synthesized by reaction of azodiisobutyronitrile and dithiobenzoic acid under the catalyzed by dimethylsulfoxide,and dithiobenzoic acid was obtained from the acidification of dithiobenzoic acid brominated magnesium salt by hydrochloric acid.The dithiobenzoic acid brominated magnesium salt was prepared by the reaction of carbon disulfide and Grignard reagent formed from the reaction of bromobenzene and magnesium powder.The resulting CPDB was characterized by 1H-NMR,FT-IR.Reaction temperature,dropping rate of bromobenzene,reaction time e.t.c.factors affecting the yield of CPDB were discussed.Results of the experiment shows quite pure CPDB was synthesized under the optimal conditions that 40℃ of temperature and 17 hours of reaction time.2.PDMAEMA was synthesized by RAFT polymerization,using DMAEMA as monomer,CPDB as chain transfer agent and AIBN as initiator.besides,toluene was used as solvent.Reaction time,temperature,concentration of initiator and the type of chain transfer agent such factors effecting on polymerization reaction were investigated.Then PDMAEMA with a proper molecular weight was used as a macromolecular chain transfer agent for the synthesis of PDMAEMA-b-PAAAB block copolymer using AAAB as monomer and AIBN as initiator by RAPT polymerization.PDMAEMA and PDMAEMA-b-PAAAB were both characterized by FT-IR,1H NMR,GPC.The results shows CPDB is more controllable to RAFT polymerization than CDB for higher chain transfer constant.Molecular weight of block polymer increased linearly with the conversion of AAAB,and block copolymer obtains narrow molecular weight distribution,which is below 1.5.In addition,the kinetic curves of polymerization demonstrate good linear relationship.3.The micelle of PDMAEMA-b-PAAAB was prepared by dialysis method in water,and the pH-responsibility,particle size and the morphology of the micelle were investigated by UV-spectrophotometer,nanometer particle sizer and transmission electron microscope respectively.The result shows micelle solution and the particle diameter of PDMAEMA-b-PAAAB involves photo-responsibility for UV-light.The micelle particles with the size of 200 nm appear globularity,which can be used for investigate further.