Abstract: Carbon fibers having balanced properties comprising an ultra-high modulus greater than 100 Mpsi and a high tensile strength of greater than 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.

Abstract: Carbon fibers having balanced properties comprising an ultra-high modulus greater than 100 Mpsi and a high tensile strength of greater than 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.

Abstract: High modulus, high tenacity fibers of poly-p-phenylene terephthalamide (PPD-T) are manufactured comprising a fiber heat treating process for increasing the inherent viscosity and the crystallinity index of the PPD-T. Never-dried fibers swollen with water of controlled acidity are heated beyond dryness in an atmoshphere having a flow of greater than Reynolds Number 10,000 throughout the duration of the heating.