Mechanical Properties of CNT Yarn with Sulfur Cross-linked Structure

Abstract

CNT yarns produced by dry spinning are expected to be used as a next-generation carbon material to replace carbon fibers already in practical use. However, the current strength of CNT spun yarn (~0.4 GPa) is lower than that of carbon fiber (6 GPa). In order to increase the strength of CNT spun yarn, a method of cross-linking CNT bundles with sulfur has been reported in recent years. In this study, we attempted to introduce a sulfur cross-linked structure by immersing CNT yarn in a sodium polysulfide solution for a long time to increase CNT yarn's strength. The sulfur cross-linked structure suppressed "slipping," which is the breaking mechanism of CNT spun yarn, and significantly increased the strength of the CNT spun yarn to a maximum tensile breaking stress of 4.93 GPa (untreated: 0.37 GPa).