THE CHARACTERIZATION OF PAN-BASED CARBON-FIBERS DEVELOPED BY 2-STAGE CONTINUOUS CARBONIZATION

A continuous stabilization and two-stage carbonization process was use d to prepare polyacrylonitrile (PAN)-based carbon fibers. The effect o f precarbonization on the final properties of carbon fibers was measur ed. The results of this study showed that a suitable precarbonization was very conducive to improvement in tensile strength or in Young's mo dulus of the final carbon fibers. When the final carbon fiber was prec arbonized at 550-degrees-C, this fiber had a higher tensile strength t han carbon fibers which were precarbonized at other conditions. On the other hand, the final carbon fibers developed at precarbonization tem peratures of 650-degrees-C and 700-degrees-C, had better Young's modul us. Experimental results using a X-ray diffractometer indicated the pr esence of a less ordered phase at 2THETA = 17-degrees in the precarbon ized fibers and the final carbon fibers. The formation of this less or dered structure is also discussed.