Abstract:The rigid carbon fiber preform (Fiberform) was prepared by vacuum molding using chopped carbon
fibers as the raw material and thermal setting phenolic resin powder as the cross linking agent. The resulting Fiberform
was further impregnated with phenolic resin solution through reaction and drying process, to obtain phenolic impregna
ted carbon ablator (PICA). Fiberform consists of interconnected chopped carbon fiber oriented preferentially in the
horizontal direction, making it a transverse isotropic material with different material properties. The longitudinal com
pressive strength and transverse compressive strength were varied from 0. 10 to 0. 39 MPa and 0. 33 to 0. 79 MPa, re
spectively, depending on the density of Fiberform. PICA had an aerogel like composite structure consisting of phenolic
nanoparticles and carbon fiber network. The density of PICA could be controlled from 0. 27 to 0. 43 g/ cm3 by chan
ging the concentration of phenolic resin solution. The longitudinal and transverse compressive strengths of PICA were
therefore adjusted from 0. 45 to 2. 42 MPa and from 1. 36 to 2. 27 MPa, respectively. The PICA had the similar ther
mal insulation with the Fiberform, 0. 08 W/ ( m·K) in through the thickness and 0. 11 W/ ( m·K) in plane direc
tions.
