Carbon Nanotube-Directed 7 GPa Heterocyclic Aramid Fiber and Its Application in Artificial Muscles

D Yan and JJ Luo and SJ Wang and XC Han and XD Lei and K Jiao and XQ Wu and L Qian and XS Zhang and XX Zhao and JT Di and Z Zhang and ZF Gao and J Zhang, ADVANCED MATERIALS (2023).

DOI: 10.1002/adma.202306129

Poly(p-phenylene-benzimidazole-terephthalamide) (PBIA) fibers with excellent mechanical properties are widely used in fields that require impact-resistant materials such as ballistic protection and aerospace. The introduction of heterocycles in polymer chains increases their flexibility and makes it easier to optimize the fiber structure. However, the inadequate orientation of polymer chains is one of the main reasons for the large difference between the measured and theoretical mechanical properties of PBIA fibers. Herein, carbon nanotubes (CNTs) are selected as an orientation seed. Their structural features allow CNTs to orient during the spinning process, which can induce an orderly arrangement of polymers and improve the orientation of the fiber microstructure. To ensure the complete 1D topology of long CNTs (approximate to 10 mu m), PBIA is used as an efficient dispersant to overcome dispersion challenges. The p-CNT/PBIA fibers (10 mu m single- walled carbon nanotube 0.025 wt%) exhibit an increase of 22% in tensile strength and 23% in elongation, with a maximum tensile strength of 7.01 +/- 0.31 GPa and a reinforcement efficiency of 893.6. The artificial muscle fabricated using CNT/PBIA fibers exhibits a 34.8% contraction and a 25% lifting of a 2 kg dumbbell, providing a promising paradigm for high-performance organic fibers as high-load smart actuators. The damage-free single-walled carbon nanotubes (SWNTs) dispersed using poly(p-phenylene-benzimidazole-terephthalamide) (PBIA) are selected as the orientation seed to improve the fiber microstructure and the mechanical properties. The p-SWNT/PBIA fibers exhibit an increase of 22% in tensile strength and 23% in elongation, with a maximum tensile strength of 7.01 +/- 0.31 GPa and a reinforcement efficiency of 893.6.image

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