Abstract
Carbon nanotube (CNT) is an advanced material with excellent specific strength and specific stiffness, and is expected to be applied to composite materials, whose use is expanding in the aerospace field. Wet spinning and dry spinning are the two main methods of CNT yarn production. The direct spinning method, one of the dry spinning methods, uses Floating Catalyst-Chemical Vapor Deposition (FC-CVD) to continuously spin CNTs, and is considered to be capable of synthesizing high-purity CNTs. However, the strength of CNT yarns is significantly lower than that of CNTs as a single material, and there is an urgent need to increase the strength of CNT yarns by post-processing in order to expand their industrial use. In this study, we investigated the basic physical properties of CNT yarns produced by FC-CVD and evaluated the factors affecting strength. In addition, PAA/DMSO treatment was applied to increase the strength, and the fracture morphology was evaluated by observing the fractured area. From the test results, it was confirmed that CNT yarns of FC-CVD had low functional group content and high purity, and that the PAA/DMSO treatment was not effective enough. TEM observation of the fracture area showed that the CNT bundle was the smallest unit of the fracture, and it was confirmed that the CNT bundle was fractured due to slippage between CNTs, resulting in a pull-through fracture.
