Improvement in the properties of PAN-based carbon films by modification with cobaltous chloride

Abstract

Carbon films were developed from polyacrylonitrile (PAN) modified with cobalt chloride. The modification was carried out by immersing PAN in a 5% cobaltous chloride (CoCl2) solution at 90°C for 5 min, oven-dried, and then manufactured into films. The original and modified PAN films were oxidized at 220°C for 2 and 6 h in air, respectively, and finally carbonized at 1300°C. The density, microstructure, elemental analyzer, electrical conductivity, and morphology were all studied. According to the results, it was found that films modified with cobalt chloride have a greater stacking height of carbon-layer planes (Lc), density, electrical conductivity, and nitrogen content after carbonization. Moreover, during the carbonization stage, the cobalt ions promote a catalytic action. The carbon films developed from the modified film not only improved electrical conductivity by 12–38%, but also increased tensile strength by 29–36% and the tensile modulus by 69–110%. Therefore, carbon films having better mechanical properties can be obtained after such modification. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1745–1751, 1999