| Conducting polymer/inorganic magnetic composites are organic /inorganic hybrid function materials obtained from conducting polymer (such as polyaniline, polypyrrole, polythiophene and their derivatives etc) and inorganic magnetic composites (for example r-Fe2O3, Fe3O4, various ferrites and other transition metal oxides and their salts etc) by certain ways. It is the effective combination of such organic polymer with inorganic nano-materials, which generates some unique functional properties different from its components conductive polymer and inorganic magnetic material. Effective integration of the two components makes it possible to overcome their inherent drawbacks in order to meet the overall performance requirements "thin, light weight, wider frequency bands, and stronger intensity" both in modern military stealth and civilian protective fields. Therefore it is also currently the urgent bottleneck problem to solve in this important field.In this thesis, conducting composite materials with various morphologies were synthesized by soft template or hard template method using aniline and o-toluidine as monomers, and Fe3O4 ferro-fluid or cobalt salt as inorganic component. These morphologies include nano-particles, nano-fibers, string bead nano-chains, nano-branches, nano-tubes, nano-rods and nano-hollow spheres. Systematic studies were made on the composition, structure, properties and functions of the composites. The possible formation mechanism was therefore proposed.The main research results were as follows:1. POT/Fe3O4 nano-hollow sphere composites have been synthesized via template-free polymerization method. The composition and structure of products were characterized by FT-IR, TEM, XRD and TGA techniques. Room temperature conductivity and electromagnetic parameters were measured, and the absorbing properties of nano-composites were discussed. The maximum reflection loss is-2.25 dB at 11.9 GHz, and the frequency width of loss over-10 dB is 0 GHz, the microwave absorption property gets better than without doping Fe3O4.2. The morphology and structure of PAn/Fe3O4 nano-composites can be effectively tuned by dye molecules such as Congo red, Eriochrome black T and magneson during the polymerization. The composition, structure and thermal stability of products were characterized by FT-IR, SEM, XRD and TGA. Electromagnetic properties and absorbing properties were measured and studied, and the formation mechanisms were discussed. The maximum reflection loss is-4.5 dB at 12.4 GHz, and the frequency width of loss over-10 dB is 0 GHz.3. Polyaniline/CoC2O4nanocomposite with both electrical and magnetic conductivity has been synthesized by using in-situ growth of polyaniline under different conditions on the surface of nano-cobalt oxalate, which was obtained by low heating solid state reaction. The products were characterized by FT-IR, TEM, XRD and TG analysis techniques. The results indicate that the morphology and structure and their electromagnetic properties of as-prepared nanocomposites can be effectively tuned by changing the in-situ complex conditions. The optimal experimental results were as follows:polyaniline/CoC2O4 nanocomposite obtained under ultrasonication showed a maximum reflection loss of-28.8 dB at 8.6 GHz with a bandwidth of 3.2 GHz above-10 dB loss.In a word, the micro/nanocomposites prepared from the complex of conducting polyaniline or its derivatives with inorganic ferric oxide or cobalt salt show unique functions especially with vourious contollable morphologies. Of which the polyaniline nanocomposite with weak magnetic CoC2O4 exhibit both the advantages of tunable morphologies and favorable electromagnetic properties. It shows attractive application prospects both in military stealth and civilian electromagnetic protection as novel microwave absorbing materials.
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