Improved properties of Carbon nanotube yarn spun from dense and long carbon nanotube forest

Notable progress has been made recently on the properties and applications of Carbon nanotube (CNT). However, CNT has not achieved any remarkable practical applications from the industrial point of view. In this article, we report our recent progress on the bulk fiber structure of CNT yarn spun from the CNT forest. The unique fiber-like structure of CNT yarns gives them exceptional mechanical toughness, electrical conductivity, resilience to bending stress, and blend with polymer materials for a composite structure. CNT yarn, which is produced by spinning of high dense and relatively long CNT forest, has emerged as a new high-performance CNT-based bulk and composite material. We have made improvements in properties of CNT yarn by applying high voltage (HV) to the CNT yarn in a vacuum chamber. The tensile strengths of as-spun and HV-treated CNT yarns were 624 MPa and 955 MPa, respectively. The crystallization behavior of the amorphous carbon on CNTs was confirmed by a Transmission Electron Microscope (TEM). The CNT yarns provide them mechanical properties different from those of original high-performance fiber.