A study on the effect of heat treatment on functional groups of pitch based activated carbon fiber using FTIR

Pitch based active carbon fibers (ACFs) were analyzed by a FTIR micro-ATR technique by introducing a very thin KBr layer on their surfaces. The ACFs were thermally treated at 600, 1100, and 1200°C respectively, to investigate the change of their surface functionalities. As the heat treatment temperature increased, the amount of oxygen containing surface functional groups were reduced and the ACFs became more hydrophobic. When the ACFs were thermally treated, the decrease of carboxylic acid groups occurred first and ketone or quinone groups subsequently disappeared at higher heat treatment temperatures. The degree of graphitization of the ACF was increased significantly when it was treated at 1100 and 1200°C and this was partially attributed to the release of the C=O groups in the conjugated ketone or quinone structures.