Effect of CNTs growth on carbon fibers on the tensile strength of CNTs grown carbon fiber-reinforced polymer matrix composites

Carbon nanotubes and nanofibers were directly grown on carbon fiber substrate by catalytic decomposition of acetylene precursor using thermal chemical vapor deposition process. These carbon nanotubes and nanofibers coated carbon fibers were used as reinforcement in epoxy matrix for the fabrication of unidirectional composites. The morphology of carbon nanomaterials grown on carbon fibers was examined by scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM). Electron microscopic observations revealed uniform coverage of carbon fibers with carbon nanotubes, nano- fibers and filaments. The composites made of carbon nanotubes coated carbon fibers showed 69% higher tensile strength as compared to composites made of carbon fiber which had undergone similar heat treatment but without carbon nanotubes growth. The results of tensile test revealed that both the high vacuum condition and choice of an appropriate catalyst precursor strongly influence the fiber properties thereby affect the resultant properties of the composites made of these surface modified carbon fibers.