Effect of Heating Rate in Carbonization on Mechanical Properties of Polyacrylonitrile Based Carbon Fibers

Abstract

Three types of commercially available polyacrylonitrile (PAN) fibers such as Hyosung (HS), Blue star (BS), and Jilin (TL) fibers were stabilized by continuous system and followed by carbonization at 1050 C-omicron with heating rates of 2 and 10 C-omicron/min in a tubular furnace. To investigate structures of resulting carbon fibers (CFs), X-ray diffraction (XRD) and Raman spectroscopy were performed. Without regarding heating rate in carbonization and types of PAN fibers, structural properties were not significantly different. However, a lower heating rate resulted in higher tensile strength with all types of PAN fibers. CFs based on HS PAN fibers showed tensile strength of similar to 4.1 and similar to 2.6 GPa with heating rates of 2 and 10 C-omicron/min, respectively. Tensile modulus also increased with a lower heating rate, and the values of HS CFs are similar to 253 (2 C-omicron/min) to similar to 196 GPa (10 C-omicron/min). X-ray photoelectron spectroscopy (XPS) revealed that CFs prepared with slow heating contained higher content of spa even though there was no significant different in carbon content. These suggest that chemical structure play an important role in mechanical properties of CFs.