Dissertation
Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Composite materials > Non-metallic composite materials

The Preparation and Characterization of Feerimagnetic Particles/Polypyrrole (PPy) with Core-Shell Structure

Author ChenAiHua
Tutor LiXiaoYu;WangHaiQiao
School Beijing University of Chemical Technology
Course Materials Science
Keywords Polypyrrole Iron powder Fe3O4 particles Conductive Guide magnetic Composite materials
CLC TB332
Type Master's thesis
Year 2003
Downloads 410
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Conducting polymers and magnetic composite particles prepared the conductive magnetic composite material is a hot research topic in recent years. The preparation of such composite materials commonly used method is the magnetic particles coated with a conductive polymer composites synthesized by chemical polymerization. Micron-scale magnetic particles due to their own than the material, easy to precipitate in the solution, and the nanoscale magnetic particles because of the small particle size, easily aggregates so preparing a conductive composite magnetic material of the main problems to be solved is how to make the magnetic particles in the polymerization system uniformly dispersed. Of the subject of the research task is to solve the problem of the magnetic particles dispersed in an aqueous solution, prepared having excellent electrical and magnetic properties of the composite material. In this paper, micron iron powder / polypyrrole composites and nano-Fe304 particles / the polypyrrole two systems for the study, detailed discussion of the conductive composite magnetic materials Preparation and Magnetic title. Sodium dodecylbenzenesulfonate (N a DBS) Processing micron grade iron powder, to improve the status of a dispersion in an aqueous solution, and jFeCl3 for oxidizing the surface of the iron powder by emulsion polymerization, a layer of polypyrrole prepared iron powder / polypyrrole. The paper discusses the oxidant, dopant and the amount of iron powder composite electrical, magnetic. The composite material has excellent electrical properties, the sigma shape = 1 3 7 S / cm, but magnetic undesirable. max In order to prepare the electric, magnetic properties are preferably electrically permeable composite material, the subject of Fe304 nanoparticles synthesized, to make the surface organic, in order to improve its dispersion stability in an aqueous solution and then dried over anhydrous ethanol. Then, Fe304 particles nuclear emulsion polymerization prepared Fe304 / lt; WP = gt; polypyrrole. The composite material having excellent electrical, magnetic, electrical conductivity of up to 13.6 S / cm the saturation magnetic strength can be achieved 24.38 emu / g. Within the scope of the research of the present subject (Fe% = 11.4% ~ 20.6%), conductivity (7.69 S / cm to 3.6 S / cm) of the composite material is higher than that of pure polypyrrole (3.48 S / cm). The conductivity and a saturated magnetic strength increase with Fe304 content of particles in the system increases. The environmental stability of the composite material is much better than pure polypyrrole. This article also proposed a treatment method of the nano-F e 3 0 4 particles. The principle of this method is the common ion effect, Fe304 particles in FeCl3 solution can absorb a large number of Fe3 formed on the surface layer of cationic shell repulsion between ions of the same sex and improve Fe304 particles dispersed in aqueous solution. Simultaneously: Fe304 particle surface Fe3 oxidation of pyrrole monomer polymerization obtained by I ~ e304 / polypyrrole composites. Because the Fe304 surface of the particles is limited by the quantity of Fe3 low conductivity of the resulting composite material, polypyrrole coating layer thickness of approximately 1 nm, but the magnetic properties can be very strong. Adding an oxidizing agent and the monomer in the system in order to improve its conductivity, the secondary polymerization. The resulting composite material has excellent electrical and magnetic properties. Discussed in detail in the text of the concentration of FeCl3 processing liquid composite electrical, magnetic, found that the FeCl3 treatment solution concentration of 12%, the composite conductivity and saturation magnetic strength reached the highest value, respectively, to 13.73 S / cm 31.41 emu / g. In addition, the subject system the Fe304 content on composites electrical, magnetic energy, the electrical conductivity of the composite material and a saturated magnetic intensity increases with increasing system Fe304 content. Moreover, the composite material also has excellent environmental stability.

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