Developing a hybrid emulsion polymerization system to synthesize Fe3O4/polystyrene latexes with narrow size distribution and high magnetite content |
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| Authors: | Longlan Cui Hong Xu Ping He Keiko Sumitomo Yoshinori Yamaguchi Hongchen Gu |
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| Institution: | 1. National Key Laboratory of Nano/Micro Fabrication Technology, Research Institute for Micro/Nano Science and Technology, Shanghai Jiaotong University, Shanghai 200030, China;2. Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo 162‐0041, Japan;3. Yoshinori Yamaguchi, Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo 162‐0041, Japan;4. Hongchen Gu, National Key Laboratory of Nano/Micro Fabrication Technology, Research Institute for Micro/Nano Science and Technology, Shanghai Jiaotong University, Shanghai 200030, China |
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| Abstract: | A hybrid emulsion polymerization was formulated for synthesizing Fe3O4/polystyrene composite latex. This system, containing binary droplets that are magnetic (Mag)‐droplets with a diameter of 100–200 nm and styrene (St)‐droplets with a diameter of 3–4 μm, was obtained by mixing Mag‐miniemulsion and St‐macroemulsion. With extremely low surfactants concentration (?critical micelle concentration, CMC), the nucleated loci are selectively controlled in the Mag‐droplets, as the result of smaller droplet size and larger surface ratio. Both water‐soluble potassium persulfate (KPS) and oil‐soluble 2,2′‐azobis(2‐isobutyronitrile) was adopted to initiate the polymerization. In the presence of KPS, magnetic polystyrene latices with particles size of 60–200 nm, narrow size distribution, and high magnetite content (86 wt % measured by TGA) were attained successfully. The synthesized magnetic Fe3O4/polystyrene latices assembled into well‐ordered hexagonal structure in the surface of a carbon supported copper grid. The influence of various parameters on various aspects of the as‐synthesized Fe3O4/polystyrene was investigated in detail: type of initiator on composite morphology, feed ratio of Mag‐miniemulsion and St‐macroemulsion on magnetite content, and hydrophobic agent or amount of surfactant on size and size distribution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5285–5295, 2007 |
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| Keywords: | emulsion polymerization high magnetite content magnetic polymer microencapsulation miniemulsion narrow size distribution polystyrene |
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