Synthesis of hyperbranched organometallic polymers and their use as precursors to advanced ceramic materials
Lam, Wing Yip
Cha, John A.
|Source||US Patent, 6,759,502 B1, 2004|
|Summary||At present time techniques in preparing advanced ceramic materials with high electrical conductivity and magnetic susceptibility are rare. This new invention relates to hyperbranched organometallic polymers, which are useful as precursors to certain ceramic materials, processes for the preparation of such polymers and the preparation of ceramic materials from such polymers, ceramic materials and their use as ferromagnetic materials and electrically conductive materials. This Hyperbranched organometallic polymers are synthesized through the polymerization of dilithioferrocene and trichloroalkylsilanes. Pyrolysis of the hyperbranched polymers yields mesoporous, conductive, and magnetic ceramics. The three-dimensional structure of the hyperbranched polymers serves as shielding nets to keep the atom inside thereby enabling the high-yield production of the ceramic materials. Most of the hyperbranched polymer presursors of the invention are soluable in common solvents, melt at relatively low temperatures and can be processed into robust engineering forms such as thin films, which is different from the crosslinking polymer presursors as they are inherent intractable. The high iron content and the nanodimension of the iron clusters endow the ceramics with high electrical conductivity and superparamagnetic susceptibility. The saturation magnetizability of the ceramics is much higher than that from the linear polymers and the hysteresis loss is virtually zero, which means the ceramics are excellent soft ferromagnetic materials.|
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