THE INFLUENCE OF PRE-CARBONIZATION ON THE PROPERTIES OF PAN-BASED CARBON-FIBERS DEVELOPED BY 2-STAGE CONTINUOUS CARBONIZATION AND AIR OXIDATION

The properties of three kinds of carbon fibers, which were pre-carboni zed at 500, 550, and 600 degrees C during two-stage continuous carboni zation, were measured after being air oxidized for periods of 1 to 6 m in at 550 degrees C. The effects of precarbonization temperatures on m echanical properties, density, morphology, elemental compositions, and microstructure of the carbon fibers are discussed. The pre-carbonizat ion process affected strongly the surface properties and mechanical pr operties of the final carbon fibers, as measured after air oxidation. Carbon fibers measured one to six min after air oxidation showed a dif ferent oxidation behavior in the surface morphology for each pre-carbo nization temperature. Optimum conditions not only improved the tensile strength and modulus by over 50%, but also increased the density and oxygen content.