THE EFFECT OF CARBONIZATION TEMPERATURE OF PAN FIBER ON THE PROPERTIES OF ACTIVATED CARBON-FIBER COMPOSITES

The PAN (polyacrylonitrile) based carbon fiber composites were prepare d from mixtures of chopped carbon fibers and phenolic resin. Two diffe rent carbon fibers were obtained by carbonization of stabilized PAN fi ber precursors in nitrogen at 1073 and 1273 K, respectively. Samples o f activated carbon fiber composites (ACFCs) were prepared from the car bon fiber composites by activation in carbon dioxide at 1123 K for 10- 90 minutes. The effect of carbonization temperature of a precursor fib er on the specific surface area and the bending strength of ACFCs were studied in this work. As the bum-off of ACFC made of the fiber carbon ized at 1073 K was increased from 37 to 75%, the specific surface area increased from 500 to 1100 m(2) g(-1), and the bending strength decre ased from 3.6 to 1.8 MPa. These values were about two times larger tha n those made of the fiber carbonized at 1273 K. The effect of carboniz ation temperature of a precursor fiber on the bending strength of ACFC was ascribed to the bonding strength between the carbonized fiber and phenolic resin binder, and to the density of the ACFC. (C) 1997 Elsev ier Science Ltd.