COAL-TAR PITCH AS A MATRIX PRECURSOR FOR 2-D C C COMPOSITES/

Four coal-tar pitches were used in conjunction with a woven carbon fib re cloth to produce carbon/carbon (C/C) composites in order to study t he effect of the nature of the pitch, as matrix precursor, on the prop erties of fully-processed composites. The nature of the pitch had litt le effect on the density, porosity, flexural modulus or inter-lamellar shear strength of the composites. However, the flexural strength of t he composites decreased as the quinoline insolubles (QI) content of th e precursor pitch increased. Two structural features of the composites also varied with the pitch QI content: the amount of granular carbon in inter-layer positions and the mean length of bundle voids, i.e. tho se oriented perpendicular to the cloth layers. The flexural strength c ould be related to void parameters using an equation developed from th e Knudsen equation. Copyright (C) 1996 Elsevier Science Ltd