An Evaluation of the Beneficial Effects of Polyamide 6's Thermal Stabilization by Ferric Chloride Complexation as a Novel Carbon Fiber Precursor

Abstract

This study investigated the impact of stabilization time on pretreated polyamide 6 (PA6) fibers using various analytical techniques, including thermal analysis (TGA and DSC), infrared (IR) spectroscopy, X-ray diffraction (XRD), tensile testing, and density measurements. The two-step atmospheric air-based stabilization process for pretreated PA6 multifilament bundles involved initial thermal stabilization at 170 °C in an air atmosphere after ferric chloride impregnation, followed by a second step of thermal stabilization at 245 °C. Ferric chloride impregnation followed by thermal stabilization in an air atmosphere resulted in crucial structural transformations. The density values of the samples increased following thermal stabilization, accompanied by a decrease in tensile values. Ferric chloride pretreated and thermally stabilized PA6 fibers were found to be fully stabilized after 120 min of stabilization before the carbonization stage. The findings obtained from the DSC, XRD, and IR spectroscopy methods indicated the occurrence of disordering phases due to the scission of hydrogen bonds. The TGA findings showed significant increases in carbon yield percentages at 500 °C and 850 °C, reaching 71.4% and 63.5%, respectively, for the sample heat treated at 245 °C for 120 min. The addition of ferric chloride is expected to potentially reduce processing costs for final carbon fiber production by decreasing the time required for the thermal stabilization of PA6.