High-temperature cross-linking of carbon nanotube multi-yarn using polyvinylpyrrolidone as a binding agent

Abstract

Carbon nanotube (CNT) multi-yarn was cross-linked together at elevated temperatures using a polymer, with the intent of improving their strength and electrical conductivity. They were functionalized using an acid treatment and immersed in a bath of different concentrations (0.5%, 0.1%, and 0.2%) of polyvinylpyrrolidone (PVP). Then they were placed in an oven at various temperatures (180 degrees C, 200 degrees C, and 220 degrees C) in order to cause cross-linking among the carbon nanotube yarns. The physical, chemical, electrical, and mechanical properties of the cross-linked yarns were investigated. The yarns cross-linked at higher temperatures and greater concentrations of PVP had a greater increase in linear mass density, indicating that the cross-linking process had worked as expected. Yarns that were cross-linked at lower temperatures had greater tensile strength and better specific electrical conductivity. Those that were treated with a greater concentration of polymer had a greater ultimate tensile strength. All these results are encouraging first step, but still need further development if CNT yarn is to replace copper wire.