Page 153 - Carbon Nanotube Fibres and Yarns

146 Carbon Nanotube Fibers and Yarns

Fig. 7.7 SEM images of FIB milled rub-densified yarn cross sections. (A) Low-pressure
rub-densified CNT yarn with a high-density sheath and a low-density core and (B)
high-pressure rub-densified CNT yarn showing a uniform CNT packing density and a
flat cross section [29]. (Reprinted with permission from M. Miao, Production, structure and
properties of twistless carbon nanotube yarnswith a high density sheath, Carbon 50 (13)
(2012) 4973–4983.)

30 µm 30 µm 30 µm 30 µm
(A) (B) (C) (D)

300 nm 300 nm 300 nm 300 nm
(E) (F) (G) (H)
Fig. 7.8 Die-drawn CNT yarns. SEM images showing cross sections of CNT yarns with
diameters of (A, E) 30 μm, (B, F) 35 μm, (C, G) 55 μm, and (D, H) 75 μm, respectively [30].
(Reprinted with permission from K. Sugano, M. Kurata, H. Kawada, Evaluation of mechan-
ical properties of untwisted carbon nanotube yarn for application to composite materials,
Carbon 78 (2014) 356–365.)

with the increase of die diameter, which means less compression during die
drawing, the density of the resulting yarn decreased. Note that the yarns
produced using the two small diameter dies (30 and 35 μm) showed similar
yarn density as the high twist CNT yarns in Fig. 7.5A.