Strong carbon-nanotube fibers spun from long carbon-nanotube arrays

New approaches have been used to spin strong carbon nanotubes (CNT) from long CNT arrays without a matrix. A continuous multi-walled (MW) CNT yarn was pulled from a high-quality array without twisting. These CNT fibers usually have a strength of ≤ 1.5 GPa and a Young's modulus of ≤ 30 GPa. These superior mechanical properties of CNT fibers are derived from the long individual CNTs in the CNT array an post spin twisting. The post-spin twisting also improved the electrical conductivities of as-spun fibers by 140%. The high strength coupled with high elongation-to-failure values makes CNT fibers very tough. Future work should focus on the synthesis of longer spinnable CNT arrays and optimization of the spinning process. Incorporating a polymer matrix into the CNT fiber should also further improve the fiber strength.