FLUORINATION OF CARBON-FIBERS BY HALOGEN FLUORIDES

Carbon fibers possess high tensile strengths and are of technological importance as reinforcing agents in composite materials. Considerable effort is being expended to modify the properties of these fibers. Tre atment with the halogen fluorides, ClF3 or BrF5, at room temperatures results in fibers having stoichiometries C1.69-2.3FX0.05-0.26 where X = Cl or Br. The electrical conductivities of such fibers vary consider ably during such treatment and eventually are reduced by about 3-4 ord ers of magnitude. However, the tensile strength of the fibers decrease s by only about 50%. Other properties of the fibers such as radius, co ntact angle, tensile strengths, and X-ray diffraction patterns as a fu nction of fluorination are investigated. Various applications are sugg ested for such fibers.