A composite carbon fiber having a carbon fiber to which an amine-functionalized polymer is electro-grafted onto a surface thereof is provided. Electro-grafting the amine-functionalized polymer onto the surface of the carbon fiber results in a composite carbon fiber in which the polymer is covalently bonded to the fiber, and in which a significant number of reactive amine groups are available for subsequent reactions, such as for reacting with a resin matrix in the production of a fiber reinforced composite. As a result, the composite carbon fibers may be particularly useful in producing fibers reinforced composites that exhibit improved interlaminar strength. Fiber reinforced composites are also provided.

A composite carbon fiber having a carbon fiber to which an amine-functionalized polymer is electro-grafted onto a surface thereof is provided. Electro-grafting the amine-functionalized polymer onto the surface of the carbon fiber results in a composite carbon fiber in which the polymer is covalently bonded to the fiber, and in which a significant number of reactive amine groups are available for subsequent reactions, such as for reacting with a resin matrix in the production of a fiber reinforced composite. As a result, the composite carbon fibers may be particularly useful in producing fibers reinforced composites that exhibit improved interlaminar strength. Fiber reinforced composites are also provided.

A functionalized carbon fiber having covalently bound on its surface a sizing agent containing epoxy groups, at least some of which are engaged in covalent bonds with crosslinking molecules, wherein each of said crosslinking molecules possesses at least two epoxy-reactive groups and at least one free functional group reactive with functional groups of a polymer matrix in which the carbon fiber is to be incorporated, wherein at least a portion of said cros slinking molecules are engaged, via at least two of their epoxy-reactive groups, in crosslinking bonds between at least two epoxy groups of the sizing agent. Composites comprised of these functionalized carbon fibers embedded in a polymeric matrix are also described. Methods for producing the functionalized carbon fibers and composites thereof are also described.

A functionalized carbon fiber having covalently bound on its surface a sizing agent containing epoxy groups, at least some of which are engaged in covalent bonds with crosslinking molecules, wherein each of said crosslinking molecules possesses at least two epoxy-reactive groups and at least one free functional group reactive with functional groups of a polymer matrix in which the carbon fiber is to be incorporated, wherein at least a portion of said crosslinking molecules are engaged, via at least two of their epoxy-reactive groups, in crosslinking bonds between at least two epoxy groups of the sizing agent. Composites comprised of these functionalized carbon fibers embedded in a polymeric matrix are also described. Methods for producing the functionalized carbon fibers and composites thereof are also described.