Page 126 - Carbon Nanotube Fibres and Yarns

118 Carbon Nanotube Fibers and Yarns

Pristine MWCNT
bundles

One MWCNT bundle

GO infiltrated
MWCNT bundles

GO SiO 2

250 nm
GO size < 50nm

Fig. 6.8 (A) SEM image of an as-spun CNT fiber surface (top view), (B) schematic 3D
model of CNT bundles intertwined with each other, (C) AFM image of a single GO
particle on a SiO 2 surface, and (D) schematic 3D model of GO infiltrated CNT bundles.
(Reproduced with permission from Y. Wang, G. Colas, T. Filleter, Improvements in the me-
chanical properties of carbon nanotube fibers through graphene oxide interlocking, Carbon
98 (2016) 291–299.)

6.7 Irradiation
Electron- and ion-beam irradiations have been employed to engineer
CNTs and strengthen CNT assemblies. Miao et al. [59] used gamma ir-
radiation posttreatment in the air to increase the lateral interactions be-
tween CNTs within fibers spun from CNT arrays, as shown in Fig. 6.9A.
The irradiated CNT fibers exhibited a significant enhancement in their
mechanical performance with an increase in the average breaking stress
from 0.66 to 0.84 GPa whereas their average Young’s modulus increased
from 13.9 to 23.3 GPa (Fig. 6.9B). Since the improvement in the mechan-
ical performance of the CNT fibers was accompanied by increasing con-
centration of oxygen related to the CNTs, it was hypothesized that the
improved mechanical properties of the fibers may stem from the chemical
reaction and the resulted CNT cross-links.