The invention is related to a continuous system for coating carbon fibre materials and a device developed to carry out the method. The coating of carbon fibre with both an electrochemical method following the polymerization (polyethylenedioxythiophene, polypyrrole, polythiophene, polyaniline and derivates thereof) of the monomer of conductive polymer and coating with an insulating sizing material (thickening material) is carried out in a single step.

Provided is a carbon fiber bundle for obtaining a fiber-reinforced resin having high mechanical characteristics. A carbon fiber bundle formed of single carbon fibers, each of which has no uneven surface structure of 0.6 m or more in length extending in the longitudinal direction of the single fiber; which has an uneven structure having a difference in height (Rpv) of 5 to 25 nm between the highest portion and the lowest portion of the surface of the single fiber and having an average roughness Ra of 2 to 6 nm; and which has a ratio of the major axis to the minor axis (major axis/minor axis) of a cross-section of the single fiber of 1.00 to 1.01, wherein a mass of the single fiber per unit length falls within the range of 0.030 to 0.042 mg/m; a strand strength is 5900 MPa or more; a strand elastic modulus measured by the ASTM method is 250 to 380 GPa; and a knot tenacity is 900 N/mm.sup.2 or more.

Provided is a carbon fiber bundle for obtaining a fiber-reinforced resin having high mechanical characteristics. A carbon fiber bundle formed of single carbon fibers, each of which has no uneven surface structure of 0.6 m or more in length extending in the longitudinal direction of the single fiber; which has an uneven structure having a difference in height (Rpv) of 5 to 25 nm between the highest portion and the lowest portion of the surface of the single fiber and having an average roughness Ra of 2 to 6 nm; and which has a ratio of the major axis to the minor axis (major axis/minor axis) of a cross-section of the single fiber of 1.00 to 1.01, wherein a mass of the single fiber per unit length falls within the range of 0.030 to 0.042 mg/m; a strand strength is 5900 MPa or more; a strand elastic modulus measured by the ASTM method is 250 to 380 GPa; and a knot tenacity is 900 N/mm.sup.2 or more.

A carbon fiber bundle containing a sizing agent particularly suitable for combination with a thermoplastic resin is provided, wherein the sizing agent has an appropriate level of bundling property for ease of handling and is susceptible to thermal degradation at temperatures low enough to maintain the surface properties of the carbon fibers, and wherein the residual amount of sizing agent can be reduced after the carbon fiber bundle is processed into an intermediate substrate, resulting in a reflection of the surface properties of the carbon fibers.

A carbon fiber bundle containing a sizing agent particularly suitable for combination with a thermoplastic resin is provided, wherein the sizing agent has an appropriate level of bundling property for ease of handling and is susceptible to thermal degradation at temperatures low enough to maintain the surface properties of the carbon fibers, and wherein the residual amount of sizing agent can be reduced after the carbon fiber bundle is processed into an intermediate substrate, resulting in a reflection of the surface properties of the carbon fibers.

Graphene has been used in nanocomposites as constituents/doping in plastics or epoxy providing dramatic enhancement of the mechanical properties but have not progressed past the laboratory level novelty. This invention can provide a graphene based composite structure with a density less that 1.9 g/cm.sup.3 for a fiber, yarn, rope or cable and a density less that 1.5 g/cm.sup.3 for a sheet both structure have tensile and shear strength greater than either Aluminum or Steel; thus providing a graphene material that is both much lighter and stronger.

A carbon fiber manufacturing apparatus includes a feeding module, a high-temperature carbonization module, a plasma surface treatment module, a sizing module, and a receiving module. A carbon fiber precursor fiber bundle released from the feeding module is sequentially processed at a predetermined speed to perform high-temperature carbonization, plasma surface treatment, sizing, and so on. The carbon fiber precursor fiber bundle is heated to form a carbon fiber, and then the surface of the carbon fiber is coated with a resin oiling agent. Particularly, through the plasma surface treatment module, the surface of the carbon fiber is roughened and provided with functional groups, which is beneficial to enhance the interface bonding of the resin oiling agent and the carbon fiber. The structure of the carbon fiber is more stable and reliable. The cost of the carbon fiber production equipment and the working time can be reduced effectively.

A carbon fiber surface oiling agent changing apparatus includes a feeding module, a receiving module, a desizing module, a plasma surface treatment module, and a sizing module. A carbon fiber yarn released from the feeding module is sequentially processed at a predetermined speed to perform the steps of desizing, plasma surface treatment, sizing, and so on, in a relatively more active and reliable manner. Particularly, the surface of the carbon fiber yarn is roughened and is provided with functional groups, which is beneficial to achieve high-quality interface bonding of the carbon fiber yarn and the matrix resin in the subsequent sizing step, thereby enhancing the characteristics of carbon fiber composite materials.

A carbon fiber manufacturing method is provided. A carbon fiber precursor fiber bundle is performed with a high-temperature carbonization step to form a carbon fiber, and then the carbon fiber is performed with a plasma surface treatment so that the surface of the carbon fiber is formed with a plasma-modified configuration which is relatively rougher. Finally, the surface of the carbon fiber is coated with a resin oiling agent to obtain the carbon fiber having the resin oiling agent thereon. Particularly, through a plasma surface treatment step, the surface of the carbon fiber is roughened and provided with functional groups, which is beneficial to enhance the interface bonding of the resin oiling agent and the carbon fiber. The structure of the carbon fiber is more stable and reliable. The cost of the carbon fiber production equipment and the working time can be reduced effectively.

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.