Reversible Addition-Fragmentation Transfer (RAFT) Living Polymerization Of Styrene Miniemulsion In The Presence Of Solubilizer

The research interest of this thesis is concentrated on the two parts: (1) styrene miniemulsion polymerization via reversible addition-fragmentation transfer (RAFT), and (2) the emulsion copolymerization of fluorine-containing methacrylate and (meth)acrylate monomers, Cyclodextrin(CD) was used as a good solubilizer both for RAFT agent (CTAs) in the styrene minimeulsion polymerization and for fluorine-containing monomer in emulsion copolymerization. The research works have been carried out and some results have been obtained as follows:(1) For RAFT polymerization system, the effects of variations on the rate of polymerization, first-order kinetics, molecular weight and molecular weight distribution have been investigated. These variations included the concentrations of CD, types and concentrations of CTAs, types and concentrations of initiators, concentrations of hexadecane (HD), reaction temperatures and various surfactants.The results of GPC and TEM analyses have confirmed that CD was very important solubilizer for the RAFT agent (2-cyanopro-2-yl dithiobenzoate). The stable miniemulsion latices were obtained, indicating the "floating red" phenomenon was successfully overcome. The molecular weights of the polymers produced were increased linearly with the conversions of the monomer. And the molecular weight distributions were in the range of 1.4 to 1.5, which was smaller than that of polymers obtained from the similar miniemulsion polymerization without solubilizer.On the base of upwards studies, the block copolymerizations of methyl methacrylate and styrene were investigated , including the ratio of monomers, the different monomer-addition sequences, concentrations of initiator and different dropping methods. Their structures were conformed by FT-IR H NMR. Their molecular weights and molecular weight distributions were analyzed by GPC.(2) (Meth)acrylate copolymer latexes containing fluorine have been prepared via emulsion copolymerization of methyl methacrylate (MMA), butyl acrylate (BA) andfluorinated monomers, 2, 2, 2-trifluoroethyl methacrylate (TFEMA) and 2, 2, 3, 3, 4, 4, 4-heptafluorobutyl methacrylate (HFBMA). FT-IR,H NMR, C NMR and 19F NMR results confirmed the incorporation of fluorinated methacrylate units in the copolymeric products. The effects of amount of TFEMA, solubilization agent cyclodextrin and polymerization conditions on the reaction rate, particle size and size distribution of latex, as well as on the copolymer properties have been investigated. The results indicated that the reaction rate increased with the increase of the reaction temperature in the range of 55 to 65 DSC and TGA results showed the reaction temperature hardly affected the copolymer constitution. The contact angles of copolymer films with fluorine were larger than that of the film without any fluorine moiety, suggesting that the fluorine-containing monomer in copolymer is in favor of improvement of the film property.