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Trace amounts of edge sites in natural graphite, synthetic graphite and high-temperature treated coke are quantitatively analyzed from the numbers of hydrogen atoms and oxygen-containing functional groups at carbon edge sites. For the analysis of hydrogen content, a new analytical technique is developed. The oxygen-containing functional groups are analyzed with a highly sensitive temperature-programmed...
Aromatic polyimides are often employed as carbon precursors to prepare in various morphologies. After a brief explanation on carbonization behavior of aromatic polyimides, structure and functionalities of carbon materials prepared from polyimides are reviewed; highly-crystalline graphite membranes, nanoporous carbon membranes, carbon foams, carbon nanofibers and carbon nanoparticles. The advantages...
The electrical and thermal conductivities in the basal plane of graphite films prepared from aromatic polyimide films were evaluated with reference to previously measured electrical and thermal conductivities along their longitudinal directions at room temperature with the aid of magnetoresistance anisotropy measurement at 77k. The average crystal-grain size of each graphite film was obtained from...
Highly crystallized graphite films were prepared from carbonized films derived from commercially available aromatic polyimide films by simple heat treatment at temperatures exceeding 3000°C. Thermal conductivity κ along the longitudinal direction of each graphite film was measured at room temperature in air by a steady-state method. Measurements of the electrical conductivity σ along the longitudinal...
Aromatic polyimide films containing cobalt compounds were prepared by mixing Co(NO 3 ) 2 and CoCl 2 with a polyamic acid in solution and following imidization on glass plates. The effect of heat treatment on structure, texture and magnetic property of the films was investigated, and the formation process of ferromagnetic particles of nano and submicron sizes in the films was...
A single nano-sized graphene sheet is prepared by a combination of electrophoretic deposition (EPD) and heat-treatment of diamond nano-particles on a highly oriented pyrolytic graphite (HOPG) substrate. Heat-treatment at 1600 o C converts diamond nano-particles to single nano-graphenes, where the mean in-plane size and the inter-layer distance from the substrate are estimated at 10-15 and...
Kapton-type polyimide film having boron-bearing functional groups in the molecule was synthesized and its carbonization/graphitization behavior was investigated by XPS, SEM, XRD, Raman spectrometry, and the measurements of electronic properties. It was found that >B-N< bonds started to form in the films around 800 o C, and these bonds were broken above 1200 o C and boron atoms...
Carbonization process of a polyimide film containing iron of 0.6 at% (Fe-PIF) was investigated in detail by the measurements of XRD and mass magnetization. Because of the existence of fine iron particles as a catalyst, the Fe-PIF films heated in a temperature range from 700 to 1200 o C showed turbostratic structure having interlayer spacing d 002 of about 0.343-0.344 nm and...
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