Studies On Electromagnetic Properties And Application Of Polymer Magnet/ Inorganic Composites

In the wake of rapid development of microwave telecommunication technology, electron devices and microstrip antennas are developing in the direction of high frequency, miniaturizing, lighteness and flatness. However, the special functional organic magnetic materials have been paid high attention to by the scientists and high-tech field. Decades of organic polymeric magnets have been synthesized by the scientists of Russia, USA, France and Japan Scince the end of 1980's last century, but their properties were very poor and less appricable value. In order to seek for multifunctional magnetic materials of lightness in weight, low electromagnetic loss and workability, the high polymeric magnet and inorganic compound are composited and made into a polymeric magnet/inorganic composite. It is based on the characteristion of the polymeric magnet that is of small specific gravity, low electromagnetic loss and workability under high frequency and microwave as well as the inorganic compound that is of high dielectric constant and good heat resistance. And it has applied the technique such as surface modification of organic acid, modification by blending, irradiation, etc. It features greater compactwave factor, low electromagnetic loss and broadened frequency band, resulting the new typical compactwavefunctional composites are of vital practical and theorical value to the modern military and telecommunication fields.The present article is based on investigation for the literatures and patented techniques at home and abroad concerning synthesis of polymeric magnet, taking ferrocene as raw material. The special molecular design is adopted to synthesize ferrocene isopthalic acylhydrazone metal coordinated polymeric magnet (OPM). It is then compounded with the chemically and physically modified inorganic compounds (rutile., TiO₂, ceramic powder, etc.) to get the polymeric magnet (OPM)/inorganic composite. The performance of the composite is characterized by means of infrared absorption spectrum (IR), nuclear magnetic resonance hydrogen spectrum (¹HNMR), gel chromatograph (GPC), X-ray diffraction (XRD), photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). It has investigated the influence of frequency, temperature, irradiated dose and surface active agent under high frequency and microwave ( 100¹800MHz) on the four important electromagnetic parameters of the composite, as well as the compactwave factor of microstrip antenna, standing wave ratio ( VSWR) and the bandwidth. The application study by electronic experts of military institutes and the colleges and universities has proved that this new composited compactwave functional material can be used to realize miniaturizing of electron device and microstrip antenna by means of the simplest structure design. Compared to the compostied dielectric material produced by the world-famous American Rogers Co, this new-type composited compactwave material can be used to reduce geometric dimension of microstrip antenna by 40%, while the bandwidth will be three times of that for dielectric antenna. It has not only solved the problem that it was unable to give simultaneous consideration of miniaturizing and band broadening in antenna design for a long time or it was of complicated structure, but also solve to the problem that the normal dielectric material below 500MHz band was unable to be applied in VHF/UHF band due to too large volume.It has studied the influence of different irradiated doses on electromagnetic property of OPM/M-type ferrite composite as well as the shielding effect of OPM/metallic fiber composite. It has also provided process selection and theoretical basis for further study on broadband absorbent and electromagnetic shielding materials. Moreover, it probes the characteristic magnetic parameters of pyrolysis product of the three ferrocenyl isophthalic acylhydrazone metals (Cu, Ni, Mn)coordinated polymer. The study shows that the pyrolysis product is a very valuable solid solution. Therefore, a new-type soft or hard magnetic materials with adjustable electromagnetic parameters can be obtained by means of pyrolysis of different transition metal coordinated polymers.Finally, it further approaches the subject of both theory and application of polymeric magnet in interdisciplinary field and prospects for the orientation of development of the discipline in the future.The ferrocenyl with Jt -bond is firstly drawn in the five membered ring having paramagnetic metal and N-N coordination to form a macromolecular conjugated system, making the electrons in the macromolecule more easily delocalized so as to obtain polymeric magnet, which is an important comtribution for the basic theoretical research of polymeric magnetism. Moreover, the composite interfacial chemical bond theory is applied to make a study of the surface modificaition of inorganic particulate with organic acid active agent. It has raised affinity of both polymeric magnet and inorganic particle to form a six-ring between the two phases, thus reducing surface activation energy of OPM/inorganic composite and causing weaker interfacial polarization. It has explained why the electromagnetic loss of modified composite is greatly reduced while dielectric constant is increased, which laid theoretical foundation to develop a composite of highly compactwave factor.To sum up, the OPM/inorganic composite mentioned in present paper can be compared with the normal dielectric materical, it is of two important and advanced features — greater compactwave function and band broadeningfunction. It is the only new type special functional compactwave material both at home and abroad, for which the most simple structure design can be applied to realize miniaturizing, band broadening and low-frequency application of electron devices and antennas (microstrip and bar-type ). It is possible to make high-frequency and microwave devices and antennas even lighter, even smaller and even thinner, which is not only an important applicable value for concealing and miniaturizing of military equipment, the frequency lowering of tactical antenna as well as intellectualization an multifunction of microwave telecommunication antenna, but also and important significance for perfecting the background research of polymeric magnet as well as the preparative technique and mechanism probing of organic/ inorganic compound particulate.