The present invention provides a carbon membrane for fluid separation with which a high-pressure fluid can be separated and purified and which has excellent pressure resistance and is less apt to be damaged. The present invention relates to a carbon membrane for fluid separation, including: a core layer which has a co-continuous porous structure; and a skin layer which has substantially no co-continuous porous structure and is formed around the core layer.

The present invention provides a carbon membrane for fluid separation with which a high-pressure fluid can be separated and purified and which has excellent pressure resistance and is less apt to be damaged. The present invention relates to a carbon membrane for fluid separation, including: a core layer which has a co-continuous porous structure; and a skin layer which has substantially no co-continuous porous structure and is formed around the core layer.

Disclosed herein are processes for preparing carbon fibers, comprising: sulfonating a polymer fiber with a sulfonating agent that is fuming sulfuric acid, sulfuric acid, chlorosulfonic acid, or a combination thereof; treating the sulfonated polymer with a heated solvent, wherein the temperature of the heated solvent is at least 95° C.; and carbonizing the resulting product by heating it to a temperature of 500-3000° C. Carbon fibers prepared according to these methods are also disclosed herein.

Disclosed herein are processes for preparing carbon fibers, comprising: sulfonating a polymer fiber with a sulfonating agent that is fuming sulfuric acid, sulfuric acid, chlorosulfonic acid, or a combination thereof; treating the sulfonated polymer with a heated solvent, wherein the temperature of the heated solvent is at least 95° C.; and carbonizing the resulting product by heating it to a temperature of 500-3000° C. Carbon fibers prepared according to these methods are also disclosed herein.

A method and precursor for making carbon fibers and the like comprising carbon black modified with at least one cyclic compound promoter. A source of the carbon black may be recycled materials such as recycled tires or recycled plastics. The carbon black is modified by attaching at least one cyclic compound promoter to the outer periphery of the carbon black.

A method and precursor for making carbon fibers and the like comprising carbon black modified with at least one cyclic compound promoter. A source of the carbon black may be recycled materials such as recycled tires or recycled plastics. The carbon black is modified by attaching at least one cyclic compound promoter to the outer periphery of the carbon black.

There is provided an oxidation heat treatment oven including a heat treatment chamber configured to heat-treat a fiber bundle that is an aligned acrylic fiber bundle in an oxidizing atmosphere to form an oxidized fiber bundle; a slit-shaped opening configured to take the fiber bundle in and out of the heat treatment chamber; guide rollers installed at both ends of the heat treatment chamber and configured to turn the fiber bundle back; a hot air supply nozzle that has a longitudinal axis along the width of the fiber bundle traveling and that blows out hot air, in a direction substantially parallel to a traveling direction of the fiber bundle, above and/or below the fiber bundle traveling in the heat treatment chamber; and a suction nozzle configured to suck the hot air blown out from the hot air supply nozzle, in which the hot air supply nozzle satisfies disclosed conditions (1) to (3).

There is provided an oxidation heat treatment oven including a heat treatment chamber configured to heat-treat a fiber bundle that is an aligned acrylic fiber bundle in an oxidizing atmosphere to form an oxidized fiber bundle; a slit-shaped opening configured to take the fiber bundle in and out of the heat treatment chamber; guide rollers installed at both ends of the heat treatment chamber and configured to turn the fiber bundle back; a hot air supply nozzle that has a longitudinal axis along the width of the fiber bundle traveling and that blows out hot air, in a direction substantially parallel to a traveling direction of the fiber bundle, above and/or below the fiber bundle traveling in the heat treatment chamber; and a suction nozzle configured to suck the hot air blown out from the hot air supply nozzle, in which the hot air supply nozzle satisfies disclosed conditions (1) to (3).

A carbon fiber precursor fiber bundle includes: acrylamide-based polymer fibers, wherein the carbon fiber precursor fiber bundle contains single fibers having a circular cross section in a proportion of 30 to 100%, wherein the circular cross section has a ratio of a major axis to a minor axis of 1.0 to 1.3 in a cross section orthogonal to a longitudinal direction of the single fiber, and a fineness of the single fiber is 0.1 to 7 dtex.

A carbon fiber precursor fiber bundle includes: acrylamide-based polymer fibers, wherein the carbon fiber precursor fiber bundle contains single fibers having a circular cross section in a proportion of 30 to 100%, wherein the circular cross section has a ratio of a major axis to a minor axis of 1.0 to 1.3 in a cross section orthogonal to a longitudinal direction of the single fiber, and a fineness of the single fiber is 0.1 to 7 dtex.