COMPARATIVE ANALYSIS OF KEVLAR, PBO AND DERIVED CARBON FIBERS

Carbon fiber (CF) reinforced carbon/carbon composites (CCCs) are in increasing demand in the automotive, aerospace, and defense industries due to their robust mechanical and thermal properties. Widespread application of these advanced materials is limited because of excessive production costs which are driven up due to long, expensive densification processes. Poly(pphenylene terephthalamide) (Kevlar) and poly(p-phenylene-2,6-benzobisoxazole) (PBO) are high-performance polymer fibers that can be converted to CFs via rapid carbonization processes without oxidative stabilization. Single-step carbonization of polymer fiber reinforced polymer composites has the potential to offer CCCs with an optimized pore morphology. While these precursor fibers initially cost more than PAN- and pitch-based CF, the pore structure generated from simultaneous carbonization of fiber and matrix has the potential to offset those costs via facile densification. This study investigates Kevlar and PBO fibers that were treated under different thermal schedules up to 1200 °C. Raman spectroscopy was used to compare the generated carbon structures. For both Kevlar and PBO, 1000 °C was found to produce the most ordered carbon fibers. The tensile strength of Kevlar and PBO fibers carbonized at 1000 °C is 0.726 ± 0.113 and 0.456 ± 0.050 GPa respectively. The carbon microstructure was investigated using scanning electron microscopy (SEM). Kevlar and PBO present unique characteristics that make them attractive candidates as fiber reinforcement in single-step CCCs.