Balanced ultra-high modulus and high tensile strength carbon fibers

Abstract From the Canadian patent

Carbon fibers having balanced properties comprising an ultra-high modulus greater than 100 Mpsi and a high tensile strength of greater that 500 kpsi. The carbon fibers are derived from a solvent fractionated pitch having a mesophase content of greater than 90% by weight and a quinoline insolubles content of less than 1% by weight. A crude pitch feed is sequentially heat soaked, solvent fractionated, and extruded to form as-spun fibers. The latter are stabilized or infusibilized and then carbonized by multistage heat treatments involving separate, precarbonization carbonization, and graphitization, steps with an intermediate cooling step.