If a more rigorous engineering definition is used, the tensile strength of macroscale CNTBs is still 5–24 times that of any other types of engineering fiber, indicating the extraordinary advantages of ultralong Carbon nanotubes in fabricating superstrong fibers.
The work was done at Tsinghua University and other facilities in Beijing. Researchers were Yunxiang Bai, Rufan Zhang, Xuan Ye, Zhenxing Zhu, Huanhuan Xie, Boyuan Shen, Dali Cai, Bofei Liu, Chenxi Zhang, Zhao Jia, Shenli Zhang, Xide Li & Fei Wei.
A synchronous tightening and relaxing (STR) strategy further improves the alignment of the carbon nanotubes to increase the strength.
Superstrong fibers are in great demand in many high-end fields such as sports equipment, ballistic armour, aeronautics, astronautics and even space elevators. In 2005, the US National Aeronautics and Space Administration (NASA) launched a 'Strong Tether Challenge', aiming to find a tether with a specific strength up to 7.5GPa cm3 per gram for the dream of making space elevators. Unfortunately, there is still no winner for this challenge. The specific strength of existing fibres such as steel wire ropes (about 0.05–0.33 GPa cm3 per gram), carbon fibres (about 0.5–3.5GPa cm3 per gram) and polymer fibers (about 0.28–4.14GPa cm3 per gram) is far lower than 7.5GPa cm3 per gram). Carbon nanotubes, with inherent tensile strength higher than 100GPa and Young's modulus over 1TPa, are considered one of the strongest known materials.