Activation behaviors of isotropic pitch-based carbon fibers from electrospinning and meltspinning

Pitch fibers were prepared from identical petroleum-derived isotropic pitch precursors (IPPs) by both meltspinning and electrospinning. The fibers obtained were stabilized, carbonized, and then finally activated by steam at various conditions. The specific surface area of the noble electrospun (E-spun) fibers was calculated to be 6.4 times larger than that of meltspun (M-spun) fibers due to their finer diameter. The activation was considered as first-order reaction with frequency factor 6.55 x 10(-4) s(-1) and the activation energy of 162.3 kJ/mol for E-spun fibers, and for the M-spun fibers with respective values of 4.45 x 10(-4) s(-1) and 183.5 kJ/mol. The activation rates of the E-spun fibers were calculated to be 13-20 times faster than those of M-spun fibers in the activation temperatures. The higher activation rates for the E-spun fibers were rationalized on the basis of the higher frequency factors and the lower activation energy due to their finer diameters and less ordered structure than those of M-spun fibers. (C) 2004 Elsevier B.V. All rights reserved.