Page 163 - Carbon Nanotube Fibres and Yarns

154 Carbon Nanotube Fibers and Yarns

initial low-density (aerogel state) entangled structure in the furnace. By
lowering the concentration of nanotubes in the gas phase, through either
reduction of the precursor feed rate or increase of carrier gas flow rate, the
density of the CNT entanglement could be reduced and the CNT aerogel
could be drawn by a ratio of up to 18 and wound at high speeds over 50 m/
min, as shown in Fig. 7.15A [39]. The increased winding speed improved

Fig. 7.15 Controlling the alignment of CNTs in direct spinning by diluting the concen-
tration of CNTs in the reactor. (A) Schematic representation of the direct CNT fiber spin-
ning process. SEM image of (B) nonoriented and (C) oriented CNT fibers [39]. (Reprinted
with permission from B. Aleman, V. Reguero, B. Mas, J.J. Vilatela, Strong carbon nanotube fi-
bers by drawing inspiration from polymer fiber spinning, ACS Nano 9 (7) (2015), 7392–7398.)