Journal of Textile Science & Engineering

Direct Carbonization of High-performance Aromatic Polymers and the Production of Activated Carbon Fibers

Abstract

Yutaka Kawahara, Shunsuke Otoyama, Kazuyoshi Yamamoto, Hiroyuki Wakizaka, Yutaka Shinahara, Hideki Hoshiro, Noboru Ishibashi and Norio Iwashita

For expanding the utilization of several high-performance aromatic polymeric fibers, e.g., poly p-phenylene benzobisoxazole (PBO, Zylon®), poly p-phenylene terephthalamide (PTA, Kevlar 29®), and polyarylate (PA, Vectran®), direct carbonizing and graphitizing behaviors have been investigated. The PBO-based carbon fiber showed a typical radial texture on its fracture surface, and the graphitization degree (P1) reached 0.35 and crystallite sizes of Lc(002), La(110) after graphitization exceeded 30 nm. On the other hand, the P1 indices of the graphitized carbon fibers from PTA and PA were no more than 0.15. However, a low P1 value is preferable for the production of activated carbon fibers (ACF). In addition, on the surface of the PA-based carbon fibers produced at 900°C, some fine mesh-like morphologies were observed indicating the formation of a porous carbon structure. In contrast, for the PTA-based carbon fibers the development of radial texture could be seen only partially on the fracture surface, and porous morphologies were not recognizable. It was confirmed that the direct carbonization was enough to convert PA fibers into ACF. The BET surface area of the PA-based carbon fibers increased up to 900~1,000 m2/g after the direct carbonization at 900 oC, and exceeded 1,000 m2/g easily when activated.