The present invention provides: a carbon fiber bundle which exhibits excellent filament shape stability when forming a composite material, and a carbon fiber composite material which exhibits high tensile strength; and a method for producing the same. The provided carbon fiber bundle exhibits a tensile elasticity as a resin-impregnated strand of 265-300 GPa, a tensile strength as a resin-impregnated strand of 6.0 GPa or more, a knot strength of 820 N/mm.sup.2 or more, a filament number of 30,000 or more, and an average tear distance of 600-850 mm, wherein the rate of change in filament width is 8% or less when the carbon fiber bundle is unraveled under the conditions stipulated in the description, and there are four or fewer sections per 1,000 m which exhibit a filament width equal to or less than 75% of the average filament width when the carbon fiber bundle is unraveled under the conditions stipulated in the description.

The present invention provides: a carbon fiber bundle which exhibits excellent filament shape stability when forming a composite material, and a carbon fiber composite material which exhibits high tensile strength; and a method for producing the same. The provided carbon fiber bundle exhibits a tensile elasticity as a resin-impregnated strand of 265-300 GPa, a tensile strength as a resin-impregnated strand of 6.0 GPa or more, a knot strength of 820 N/mm.sup.2 or more, a filament number of 30,000 or more, and an average tear distance of 600-850 mm, wherein the rate of change in filament width is 8% or less when the carbon fiber bundle is unraveled under the conditions stipulated in the description, and there are four or fewer sections per 1,000 m which exhibit a filament width equal to or less than 75% of the average filament width when the carbon fiber bundle is unraveled under the conditions stipulated in the description.

A method and apparatus for manufacturing a carbon fiber. Pressure is applied to a filament to change a cross-sectional shape of the filament and create a plurality of distinct surfaces on the filament. The filament is converted into a graphitic carbon fiber having the plurality of distinct surfaces. A plurality of sizings is applied to the plurality of distinct surfaces of the graphitic carbon fiber in which the plurality of sizings includes at least two different sizings.

A method of manufacturing a graphene fiber is provided. The method includes preparing a source solution including graphene oxide, supplying the source solution into a coagulation solution to form a graphene oxide fiber, reducing the graphene oxide fiber to form a primary graphene fiber, and Joule-heating the primary graphene fiber to form a secondary graphene fiber.

A method of manufacturing a graphene fiber is provided. The method includes preparing a source solution including graphene oxide, supplying the source solution into a coagulation solution to form a graphene oxide fiber, reducing the graphene oxide fiber to form a primary graphene fiber, and Joule-heating the primary graphene fiber to form a secondary graphene fiber.

Systems and methods are provided for fabrication of enhanced carbon fiber laminates that utilize encapsulated catalyst. One embodiment is a method that includes acquiring a batch of dry fibers, and acquiring a batch of catalyst capsules that each comprise catalyst that accelerates polymerization of monomers of a resin, and a shell that encapsulates the catalyst and liquefies at a curing temperature. The method further includes interspersing the catalyst capsules among the dry fibers, and impregnating the fibers with the resin after interspersing the catalyst capsules with the fibers.

Systems and methods are provided for fabrication of enhanced carbon fiber laminates that utilize encapsulated catalyst. One embodiment is a method that includes acquiring a batch of dry fibers, and acquiring a batch of catalyst capsules that each comprise catalyst that accelerates polymerization of monomers of a resin, and a shell that encapsulates the catalyst and liquefies at a curing temperature. The method further includes interspersing the catalyst capsules among the dry fibers, and impregnating the fibers with the resin after interspersing the catalyst capsules with the fibers.

The invention relates to a method for producing graphene fibres, comprising the following steps: a. providing single- or multi-layer graphene or graphene oxide platelets based on graphene or graphene oxide; b applying a transition metal or a transition metal oxide to the graphene or graphene oxide platelets by means of a deposition method; c. spinning, in particular wet-spinning or dry-spinning, a graphene fibre or graphene oxide fibre by injecting a spinning solution, in which the graphene or graphene oxide platelets obtained in step b) are dispersed; d. treating, in particular reducing, the graphene fibre or the graphene oxide fibre in a process atmosphere containing a reducing agent, in particular hydrogen, at a determined treatment temperature; wherein, where there is a graphene oxide fibre, this is reduced to form a graphene fibre, wherein the graphene fibre or graphene oxide fibre is treated in such a way that the transition metal oxide in step d) is only partially reduced or the transition metal in a step following step d) is partially oxidised, wherein the partial reducing or partial oxidation occurs, in particular in such a way that there is a certain proportion of the transition metal oxide in the finished graphene fibre that is smaller than the proportion of the transition metal, in particular smaller than 10 wt. %.

The invention relates to a method for producing graphene fibres, comprising the following steps: a. providing single- or multi-layer graphene or graphene oxide platelets based on graphene or graphene oxide; b applying a transition metal or a transition metal oxide to the graphene or graphene oxide platelets by means of a deposition method; c. spinning, in particular wet-spinning or dry-spinning, a graphene fibre or graphene oxide fibre by injecting a spinning solution, in which the graphene or graphene oxide platelets obtained in step b) are dispersed; d. treating, in particular reducing, the graphene fibre or the graphene oxide fibre in a process atmosphere containing a reducing agent, in particular hydrogen, at a determined treatment temperature; wherein, where there is a graphene oxide fibre, this is reduced to form a graphene fibre, wherein the graphene fibre or graphene oxide fibre is treated in such a way that the transition metal oxide in step d) is only partially reduced or the transition metal in a step following step d) is partially oxidised, wherein the partial reducing or partial oxidation occurs, in particular in such a way that there is a certain proportion of the transition metal oxide in the finished graphene fibre that is smaller than the proportion of the transition metal, in particular smaller than 10 wt. %.

Disclosed is a method for mass-producing densified carbon nanotube fiber. The method includes preparing carbon nanotube fiber, swelling the carbon nanotube fiber by applying an acid solution thereto, and stretching the carbon nanotube fiber, coagulating the stretched carbon nanotube fiber so as to remove the acid solution present therein, and drying the coagulated carbon nanotube fiber.