New technique to receive carbon nanotube fibers with larger dynamic power – Uplaza

In a examine revealed in Science on June 21, Prof. Jian Muqiang from Peking College and the Beijing Graphene Institute and others developed a method to manufacture carbon nanotube fibers with the dynamic power as much as 14 GPa.

Light-weight and excessive power are perpetual pursuits for fiber supplies. In response to the appliance necessities of fibers in excessive pressure charge situations equivalent to battlefield safety and house particles seize, it’s of great significance to develop fiber supplies with ultra-high dynamic power and excessive power absorption functionality.

Carbon nanotubes, with their wonderful properties of being light-weight, sturdy, excessive modulus, extremely electrical and thermally conductive, are thought of one of many perfect constructing blocks for the following era of high-performance fibers, promising to satisfy the wants of excessive pressure charge functions.

Nonetheless, attributable to points associated to fiber meeting construction, the tensile power of carbon nanotube fibers stays lower than 10 GPa, far beneath their perfect power, 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 inside the fibers, reaching a breakthrough in each quasi-static and dynamic power.

The cross-scale ordered meeting of carbon nanotubes endows the fibers with wonderful mechanical properties. The quasi-static power 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 impression safety efficiency of the carbon nanotube fibers, a mini-split Hopkinson stress bar was employed to check the mechanical habits of the fibers below excessive pressure charge loading. The outcomes indicated that because the tensile charge elevated, the fibers skilled a transition from ductile to brittle failure habits, rendering the fibers important strain-rate-strengthening results. When the pressure charge was roughly 1,400 s^–1, the dynamic power 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 below simulated ballistic impression loading. The outcomes confirmed that the precise power dissipation energy of the fibers reached (8.7 ± 1.0) × 10¹³ m kg^–1 s^–1, far exceeding that of conventional ballistic fibers equivalent to Kevlar.

These findings indicated that carbon nanotube fibers have nice potential for utility in impression 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 steered 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 power, maintain potential for functions in aerospace and impression safety. This examine supplies a possible path to harness the intrinsic power of particular person carbon nanotube on the macroscale to manufacture impact-resistant fibrous supplies.