Evaluating the stabilization of isotropic pitch fibers for optimal tensile properties of carbon fibers

Abstract

The stabilization effects of isotropic pitch fibers on the tensile properties of the resulting carbon fibers were systematically studied to develop a simple method for finding a suitable degree of stabilization. As the stabilization temperature (250-290 degrees C) and duration (30-180 min) increased, the densities of the stabilized fibers increased from 1.31 to 1.47 g/cm(3), indicating that oxygen up-take and chemical reactions led to changes in their chemical compositions. Stabilized fibers with higher densities resulted in lower density carbon fibers due to the removal of oxygen-related gases during carbonization. Each stabilization temperature had an optimal duration for obtaining high tensile strengths, which was correlated with the oxygen content after stabilization. Interestingly, when the stabilized fibers had densities of 1.35-1.36 g/cm(3), the resulting carbon fibers showed the highest tensile strength regardless of the stabilization conditions. Therefore, it is suggested that the density of the stabilized isotropic pitch fibers is a reasonable index for the evaluation of the degree of stabilization for producing high-performance carbon fibers. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All.rights reserved.