Effect of additional heat-treatment temperature on chemical, microstructural, mechanical, and electrical properties of commercial PAN-based carbon fibers

Abstract

In this present work, the effect of additional heat-treatment (AHT) in the range from 1800oC to 2400oC on the chemical composition, morphology, microstructure, tensile properties,electrical resistivity, and thermal stability of commercial polyacrylonitrile (PAN)-based carbon fibers was explored by means of elemental analysis, electron microscopy, Xray diffraction analysis, single fiber tensile testing, two-probe electrical resistivity testing,and thermogravimetric analysis. The characterization results were in agreement with each other. The results clearly demonstrated that AHTs up to 2400oC played a significant role in further contributing not only to the enhancement of carbon content, fiber morphology, and tensile modulus, but also to the reduction of fiber diameter, inter-graphene layer distance,and electrical resistivity of “as-received” carbon fibers without AHT. The present study suggests that key properties of commercial PAN-based carbon fibers of an intermediate grade can be further improved by proprietarily adding heat-treatment without applying tension in a batch process.