Compressive properties of carbon/carbon composites reinforced by carbon nanotubes with different orientations and lengths

Carbon nanotubes (CNTs) with different orientation and lengths were grafted onto carbon fibers by catalytic chemical vapor deposition to produce hybrid preforms that were used to reinforce carbon/carbon (C/C) composites. Compressive property tests indicated that these C/C composites have obvious improvements in out-of-plane compressive strength, compared with pure C/C composites. Furthermore, the improvement has strongly influenced by the orientation and length of CNTs. Compared with entangled CNTs and radially-grown straight CNTs with smaller length, CNTs with a radial grafting morphology and longer length can reinforce the F/M interface and the whole matrix more efficiently and then increase the compressive strength better.