INFLUENCE OF OXIDATION CONDITIONS ON POLYACRYLONITRILE-BASED, ACTIVATED HOLLOW CARBON-FIBERS

Polyacrylonitrile hollow fibers are oxidized at three different temper atures and various durations, and then further carbonized in nitrogen and activated with carbon dioxide. The influence of oxidation conditio ns on the properties of the resulting activated hollow carbon fibers i s discussed. Activated hollow carbon fibers at the highest oxidation t emperature have the lowest mechanical properties, and stick together o n the surface due to quick heating during oxidation. The higher the ox idation temperature, the larger the size of the pores, and the pores a re almost always concentrated at the center of the wall of the hollow fiber. However, activated hollow carbon fibers at the lowest oxidation temperature have higher mechanical properties, fewer pores of large s ize, and larger surface areas, which exhibit greater hysteresis effect s in nitrogen adsorbing at low pressure.