44 results about "Isotropic pitch" patented technology

A mixture of carbon-containing fibers, such as mesophase or isotropic pitch fibers, a suitable matrix material, such as a milled pitch is compressed while resistively heating the mixture to form a carbonized composite material. Preferably, the carbonized material has a density of at least about 1.30 g / cm3. Preferably, the composite material is formed in less than ten minutes. This is a significantly shorter time than for conventional processes, which typically take several days and achieve a lower density material. A treating component may be impregnated into the composite. Consequently, carbon / carbon composite materials having final densities of about 1.6–1.8 g / cm3 or higher are readily achieved with one or two infiltration cycles using a pitch or other carbonaceous material to fill voids in the composite and rebaking.

A mixture of carbon-containing fibers, such as mesophase or isotropic pitch fibers, a suitable matrix material, such as a milled pitch is compressed while resistively heating the mixture to form a carbonized composite material. Preferably, the carbonized material has a density of at least about 1.30 g / cm3. Preferably, the composite material is formed in less than ten minutes. This is a significantly shorter time than for conventional processes, which typically take several days and achieve a lower density material. A treating component may be impregnated into the composite. Consequently, carbon composite materials having final densities of about 1.6-1.8 g / cm3 or higher are readily achieved with one or two infiltration cycles using a pitch or other carbonaceous material to fill voids in the composite and rebaking.

A method of manufacturing an isotropic pitch-based carbon fiber spun yarn fabric includes the following steps of: obtaining composite yarn by winding a water-soluble polymer fiber around a surface of isotropic pitch-based carbon fiber spun yarn; obtaining a composite yarn fabric by weaving the composite yarn; and obtaining the isotropic pitch-based carbon fiber spun yarn fabric by dissolving and removing the water-soluble polymer fiber from the composite yarn fabric.

A process for producing a carbon foam heat sink is disclosed which obviates the need for conventional oxidative stabilization. The process employs mesophase or isotropic pitch and a simplified process using a single mold. The foam has a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts. The foam material can be made into a composite which is useful in high temperature sandwich panels for both thermal and structural applications. The foam is encased and filled with a phase change material to provide a very efficient heat sink device.

The invention discloses a production method of mesophase pitch. The production method of the mesophase pitch comprises the following steps of using petroleum pitch as a raw material, adding an additive, under protection of nitrogen, conducting thermal treatment at 380-420 DEG C for 2-10 hours, subjecting organic molecules in the additive to a heterogeneous nucleation and condensation reaction with ash in the raw material used as cores to form anisotropic pitch microbeads which wrap the ash, at 300-380 DEG C, standing and conducting sedimentation for 2-10 hours, separating out upper-layer isotropic pitch and lower-layer anisotropic pitch, taking the upper-layer isotropic pitch as a raw material, and under protection of nitrogen, conducting thermal treatment at 380-420 DEG C for 5-15 hours to obtain the high-quality mesophase pitch. By adopting the method, the high-quality mesophase pitch with an ash content lower than 50 ppm can be produced. By circularly purifying the raw material, ultra-pure mesophase pitch with an ash content lower than 25 ppm can be produced, and the ultra-pure mesophase pitch with the ash content lower than 25 ppm can be used as a raw material of mesophase pitch carbon fibers, high-purity graphite and mesophase pitch foamy carbon.

Method for making carbon-carbon composite friction product, by: fabricating carbon fiber preform; heat-treating the carbon fiber preform; infiltrating the carbon fiber preform with a high carbon-yielding pitch using VPI (vacuum pressure infiltration) or resin transfer molding (RTM) processing; carbonizing the preform with an intermediate heat-treatment at 800-2000° C.; repeating the pitch infiltration and carbonization steps to achieve a final density of >1.75 g / cc; machining the surfaces of the preform; and applying an oxidation protection system. This approach overcomes problems inherent in lower density carbon-carbon composites by employing high carbon-yielding pitches to densify the carbon-carbon composites to a high density. The high carbon yielding pitches may include isotropic pitches, 100% anisotropic (mesophase) pitches, or mixtures of the two. They may be derived from petroleum, coal tar, or synthetic feedstocks.