In a research revealed in Science on June 21, Prof. Jian Muqiang from Peking College and the Beijing Graphene Institute and others developed a technique to manufacture carbon nanotube fibers with the dynamic energy as much as 14 GPa.
Light-weight and excessive energy are perpetual pursuits for fiber supplies. In response to the appliance necessities of fibers in excessive pressure fee situations reminiscent of battlefield safety and house particles seize, it’s of serious significance to develop fiber supplies with ultra-high dynamic energy and excessive vitality absorption functionality.
Carbon nanotubes, with their wonderful properties of being light-weight, sturdy, excessive modulus, extremely electrical and thermally conductive, are thought-about one of many preferrred constructing blocks for the subsequent technology of high-performance fibers, promising to fulfill the wants of excessive pressure fee purposes.
Nonetheless, resulting from points associated to fiber meeting construction, the tensile energy of carbon nanotube fibers stays lower than 10 GPa, far under their preferrred energy, indicating substantial room for enchancment.
Researchers together with Prof. Wu Xianqian from the Institute of Mechanics of the Chinese language Academy of Sciences (CAS), Assoc. Prof. Gao Enlai from Wuhan College, Prof. Zhang Yongyi from the Suzhou Institute of Nano-Tech and Nano-Bionics of CAS, and others, subsequently proposed an progressive multi-scale structural optimization technique.
Firstly, the carbon nanotube fibers produced by floating catalyst chemical vapor deposition have been purified and functionalized. Then, the fibers have been subjected to progressive stretching in a chlorosulfonic acid (CSA) resolution containing poly(p-phenylene-2,6-benzobisoxazole) (PBO), adopted by mechanical densification. This technique results in enhancements in interfacial interactions, nanotube alignment, and densification throughout the fibers, reaching a breakthrough in each quasi-static and dynamic energy.
The cross-scale ordered meeting of carbon nanotubes endows the fibers with wonderful mechanical properties. The quasi-static energy of the carbon nanotube fibers reaches 8.2 GPa, and the standard ballistic efficiency analysis index, Cunniff velocity, exceeds 1100 m/s. As well as, the fibers exhibit good electrical conductivity.
To reveal the influence safety efficiency of the carbon nanotube fibers, a mini-split Hopkinson stress bar was employed to check the mechanical conduct of the fibers underneath excessive pressure fee loading. The outcomes indicated that because the tensile fee elevated, the fibers skilled a transition from ductile to brittle failure conduct, rendering the fibers important strain-rate-strengthening results. When the pressure fee was roughly 1,400 s–1, the dynamic energy of the fibers reached 14 GPa, surpassing all different high-performance fibers.
To research the dynamic response of the fibers, a laser-induced high-velocity transverse-impact testing was constructed underneath simulated ballistic influence loading. The outcomes confirmed that the precise vitality dissipation energy of the fibers reached (8.7 ± 1.0) × 1013 m kg–1 s–1, far exceeding that of conventional ballistic fibers reminiscent of Kevlar.
These findings indicated that carbon nanotube fibers have nice potential for software in influence protecting engineering.
The synergistic enhancement of interfacial interactions, nanotube alignment, and densification of carbon nanotube fibers is essential for his or her wonderful mechanical properties. In-situ Raman testing and molecular dynamics simulations indicated that sturdy interactions between PBO and carbon nanotubes improve intertube interactions and stress switch.
Coarse-grained simulation outcomes prompt that in progressive stretching, the addition of PBO reduces fiber porosity, will increase density, and reduces stress focus.
Underneath high-speed loading situations, a better proportion of carbon nanotubes within the fibers break, and the fiber fracture mode transitions from intertube sliding to extra synchronous carbon nanotube fractures, thereby endowing the fibers with superior dynamic mechanical properties.
Carbon nanotube fibers, characterised by their extraordinarily excessive dynamic energy, maintain potential for purposes in aerospace and influence safety. This research supplies a possible path to harness the intrinsic energy of particular person carbon nanotube on the macroscale to manufacture impact-resistant fibrous supplies.
Extra info:
Xinshi Zhang et al, Carbon nanotube fibers with dynamic energy as much as 14 GPa, Science (2024). DOI: 10.1126/science.adj1082
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Chinese language Academy of Sciences
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New technique to receive carbon nanotube fibers with larger dynamic energy (2024, June 27)
retrieved 28 June 2024
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