Patent ID: 8415420

Claim:
A carbon fiber composite material produced by providing first carbon nanofibers produced by a vapor growth method; oxidizing the first carbon nanofibers to obtain second carbon nanofibers having an oxidized surface, the second carbon nanofibers having a surface oxygen concentration measured by X-ray photoelectron spectroscopy (XPS) of 2.6 to 4.6 atm % and a ratio (D/G) of a peak intensity D at around 1300 cm −1 to a peak intensity G at around 1600 cm −1 measured by Raman scattering spectroscopy of 0.12 to 0.22; and mixing the second carbon nanofibers into an elastomer, and uniformly dispersing the second carbon nanofibers in the elastomer by applying a shear force to obtain a carbon fiber composite material.