E-120 Pitch-based Carbon Fiber by Core Level and Valence Band XPS

Both XPS core level and valence band spectra were obtained from an E-120 high modulus pitch-based carbon fiber surface. The XPS data show that the E-120 fiber had the least oxygen content on the surface compared to various other pitch-based (e.g., E-35, E-75,P-55X, etc.) and PAN based carbon fibers (e.g., AU4, TypeII, etc.). [See Y. Xie and P. M. A. Sherwood, Appl. Spectrosc. 43, 1153 (1989); Chem. Mater. 1, 427 (1989); 2, 293 (1990); Appl. Spectrosc. 44, 797 (1990); Chem. Mater. 3, 164 (1991); Appl. Spectrosc. 44, 1621 (1990); 45, 1158 (1991); Y. Xie, T. Wang, O. Franklin, and P. M. A. Sherwood, ibid. 46, 645 (1992).] E-120 also had the most graphitic structure in both the surface and the bulk among these fiber samples as evidenced by both XPS and XRD. No nitrogen was found on E-120 and other pitch-based carbon fiber surfaces but it was found on PAN-based fibers. Our previously reported work [Y. Xie and P. M. A. Sherwood, Chem. Mater. 1, 427 (1989); 2, 293 (1990); Appl. Spectrosc. 44, 797 (1990); Chem. Mater. 3, 164 (1991); Appl. Spectrosc. 44, 1621 (1990); 45, 1158 (1991); Y. Xie, T. Wang, O. Franklin, and P. M. A. Sherwood, ibid. 46, 645 (1992)], showed that XPS valence band spectra were more sensitive to chemical environment on the fiber surface than core level spectra and could well be interpreted by X–α calculations with model components.