TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The curable resin mixture (A) comprises elastomer (at least 80-2 wt.%), radical reactive resin (20-98 wt.%), and organic peroxide (0.2-10 parts by weight per 100 parts by weight elastomer and reactive resin). The elastomer is acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, ethylene-butadiene rubber, fluorine-containing rubber, isoprene rubber, silicone rubber, acryl rubber, and/or butadiene rubber (preferably acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, and/or butadiene rubber). The fuel cell separator, cell assembly, electrode, or heat-releasing plate have (A) comprising elastomer (80-2 wt. %) and a radical reactive resin (20-98 wt. %).Preferred Process: The uncured sheet has a thickness of 0.5-3 mm and width of 20-3000 mm.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The carbon material (B) is graphite powder (preferably with a mean particle size of 0.1-150 micrometers and a lattice spacing (Co value) of at most 6.745 Angstrom), artificial graphite powder, natural graphite powder, expanded graphite powder, carbon fiber, vapor-grown carbon fiber with a fiber diameter of 0.05-10 micrometers and a fiber length of 1-500 micrometers, carbon nanotube with a diameter of 0.5-100 nm and a length of 0.01-10 micrometers, and/or carbon black. The carbon material contains 0.05-10 wt.% boron.Preferred Condition: When the carbon material is pressurized to a bulk density of 1.5 g/cm3, the powder electric resistivity in a direction perpendicular to direction of pressurization is not more than 0.07 OMEGAcm. EXAMPLE - A curable resin composition containing acrylonitrile-butadiene rubber having a Mooney viscosity of 78 (20), allyl ester resin (80), dicumyl peroxide (2), and boron-containing graphite fine powder (500) was prepared. The composition was used to produce a cured product. The resulting cured product had a volume resistivity of 5 mOMEGAcm, a contact resistance of 6 mOMEGAcm2, a thermal conductivity of 15 W/m.K, a flexural strength of 45 MPa, a flexural modulus of 14 GPa, and a flexural strength of 0.5 %.    A comparative example was made using acrylonitrile-butadiene rubber having an unmeasurable Mooney viscosity (liquid) (20), allyl ester resin (80), dicumyl peroxide (2), and boron-containing graphite fine powder (500) was prepared. The composition was used to produce a cured product. The resulting cured product had a volume resistivity of 5 mOMEGAcm, a contact resistance of 6 mOMEGAcm2, a thermal conductivity of 17 W/m.K, a flexural strength of 30 MPa, a flexural modulus of 12 GPa, and a flexural strength of 0.4 %.    The curable resin composition successfully formed a uniform sheet. The comparative example remained in a powder form and was unable to be formed into a sheet.