Raft Emulsion Polymerization And Application Of Block Polyacrylate-Latex

Recently, living/controllable free radical polymerization technique have attracted public attention due to its advantage on polymer molecular composition and structure design. Reversible addition-fragmentation chain transfer (RAFT) polymerization is one of the latest and the most promising living/controlled radical polymerization. RAFT polymerization not only can synthesize the macromolecule which had decided, such as block copolymer, grafted copolymer and star copolymer and so on, but also can effectively control the molecular weight and molecular weight distribution of the macromolecule. What’s more, comparing with the other living/controlled radical polymerization, RAFT polymerization has the merits as follows:mild reaction condition, suitable monomer, and more wider prospect for industrial application etc. Considering that the block copolymer can self-assemble to form specific morphology at different external environments and its good performance on practical application, we envision to synthesize amphiphilic block copolymer by using RAFT living/controlled radical polymerization in this article. Based on macro-RAFT agent PMAA, this paper studied the polymerization kinetics, Self-assembly principle and practicalapplicationamphiphilic block copolymer and the research work is divided into three parts.Section one:We obtained PMAA-b-PBA amphiphilic block copolymer by polymerizing MAA (methacrylic acid) and BA (butyl acrylate) monomer via reversible addition-fragmentation chain transfer (RAFT) technology. The molecular composition and structure of the block copolymer was confirmed by the measurements of1H NMR spectroscopy, gel permeation chromatography (GPC) and transmission electron microscope (TEM). The effects of two component proportion on the kinetics of polymerization of the second block PBA, the aggregation morphology of block copolymer in the methanol system and the influence of water and THF on the polymer morphology was studied.Section two:We synthesized PMAA-b-PTEMA amphiphilic block copolymer by RAFT technology in the mixture of the water and1,4-dioxane with MAA and TFEMA(2,2,2-trifluoroethyl methacrylate)as the monomers. The fluorous emulsion system was analyzed by the measurements of1H NMR、GPC、SEM、TEM and Turbiscan optical technique. The effects of various parameters such as the proportions of the second block, the solvent (different ratio of1,4-dixane/water), the solid content, pH and the reaction time for the first block on the RAFT polymerization of TFEMA monomer were investigated in this work. What’s more, the morphology and the mechanism ofself-assembling in the fluorous emulsion was analyzed. Finally, the stability of the fluoropolymer emulsionwith the different DP of PTFEMA was studied.Section three:Owing to the unconspicuous effect of TFEMA monomer on the emulsion performance. We introduce HFBA (hexafluorobutyl acrylate) and DHFMA (Dodecafluoroheptyl methacrylate) monomer to improve the performance of the emulsion. However, But it is difficult to achieve copolymers with a high content of fluorinated monomer in the pure water system. So the TFEMA monomer was taked to the emulsion system to improve final conversion of HFBA and DFHMA monomer. The different ratios of [TFEMA]0/[HFBA]0and [TFEMA]0/[DFHMA]0at the second step, the length of polyacrylate with fluorinated side chain and the particle shape was researched. Under the condition of high temperature, F elements could migrate to the surface of film. According to this characteristic, we improved the performance of the traditional latex by introducing fluorine-containing emulsion and obtained the strongly hydrophobic film. The influence of the fluorinated polyacrylate chainlength, the fluorinated emulsion ratio, the processing temperature for the film and the processing time on the surface tension of the film was studied.