JEC COMPOSITES MAGAZINE - Issue #83 - August/September 2013 - 63

Fig. 2: Knot properties of GO fibre. A: SEM image of a knotted GO fibre. B:
A tied GO fibre. C: The tied GO fibre pulled to form a knot. (The rectangle
shows its position) D: The pulled GO fibre breaks at a point far from the knot

Fig. 4: A: POM image of GO fibre (45˚ to the polarizer) B: Flexible GO woven fabric

the 1.45 draw ratio GO fibre was laid 45˚ to the polarizer under the
POM (Figure 4A). This good alignment leads to a 47 GPa tensile
modulus, which is comparable to Kevlar 29 [7]. These GO fibres
might show a dramatic increase in their tensile strength and modulus
upon high-temperature annealing, possibly beating the best carbon
fibre made from PAN and mesophase pitch. On the other hand,
stretching during spinning eliminates some of the fibre’s flexibility. It
can no longer be knotted, but it is still flexible enough to be woven
into a fabric, as shown in Figure 4B.

Electrical conductivity

Fig. 3: A: Spinning apparatus. The inset photo is a vial containing 7 wt% GO
dope. B: Specific stress-strain curves of GO fibres with different draw ratios.
C: SEM image of GO fibre surface. D: SEM image of GO fibre cross-section

3A). The draw ratios applied in this work are 1.09, 1.27 and 1.45. As
the draw ratio increases, the alignment of GO flakes within the fibre
improves. The specific stress-strain curves of these fibres in Figure 3B
show their mechanical performance.
SEM images of the GO fibre surface and cross-section are given
in Figure 3C and D. The alignment of the GO within the fibre is
observed. Mechanical properties of these GO fibres are summarized
in Table 1. The drawing-introduced alignment is further confirmed
by POM images. Obvious birefringence texture was observed while

Another fascinating property of carbon fibre is its electrical conductivity. Commercial carbon fibres have electrical conductivity
that ranges from 556 to 9,090 S/cm [8]. The team investigated the
electrical performance of these GO-based fibres. Pristine GO fibre is
not conductive due to the high oxidation content in the GO flakes.
However, these GO fibres showed 294 S/cm after annealing at
1,000˚C. At this temperature, most of the oxygen functional groups
were reduced. The electrical conductivity of reduced GO fibre
would be further improved if annealed above 2,100˚C to attain truly
graphitized carbon fibres.

Outlook
This work is still in its early stage and serves as a proof of concept.
A systematic study of the spinning process is required to determine
the optimal dope concentration, fibre diameter, coagulation, fibre
morphology and draw ratio. In addition, a detailed study of annealing over 2,100˚C is mandatory before GO-based carbon fibre can be
compared with PAN- and pitch-based carbon fibres. But the current
results are encouraging. GO-based carbon fibre might be the next
generation of carbon fibre precursors and spark new advances in the
carbon fibre industry. n
More information:
http://onlinelibrary.wiley.com/doi/10.1002/adma.201301065/pdf

Tab. 1:Mechanical properties of GO fibres spun with different draw ratios

Draw
ratio

Specific
tensile strength
(mN/tex)

Specific Elongation Tensile
modulus at break strength
(N/tex)
(%)
(MPa)

Young’s
modulus
(GPa)

1.09

104±6

10±1.6

1.64±0.12

124±8

14±1.5

1.27

126±13

20±0.6

0.84±0.08

173±4

25±1.7

1.45

156±22

41±3.5

0.61±0.10

214±38

47±8.1

References:
[1] Bacon, R.; Tang, M. M. Carbon, 1964, 2, 211.
[2] Matsumoto, T. Pure Appl. Chem., 1985, 57, 1553.
[3] Dan, B.; Behabtu, N.; Martinez, A.; Evans, J. S.; Kosynkin, D. V.; Tour, J. M.; Pasquali, M.; Smalyukh, I.
I. Soft Matter,2011, 7, 11154.
[4] Singer, L. S. Fuel, 1981, 60, 839.
[5] Paul, D. R. J. Appl. Polym. Sci., 1968, 12, 2273.
[6] Shenoy, V. B.; Reddy, C. D.; Zhang, Y. ACS Nano, 2010, 4, 4840.
[7] Kevlar Technical Guide, Aramid fibre, DuPont.
http://www2.dupont.com/Kevlar/en_US/assets/downloads/KEVLAR_Technical_Guide.pdf.
[8] Minus, M. L.; Kumar, S. JOM, 2005, 57, 52.

No83 August - September 2013 /

jec composites magazine 63
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JEC COMPOSITES MAGAZINE - Issue #83 - August/September 2013

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