Lynne Wong's PhD thesis

No differences were observed in the infrared spectra of the various cane component parts.
This indicates that all the components are composed of essentially the same constituents.
Typical Fourier transform infrared (FTIR) spectra of stalk fibre, dried in an oven at 70 °C
for 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 and 48 hours, before preparation into a KBr disc (2 mg
sample + 200 mg KBr) are shown in Fig 3.23 (bottom to top spectrum).
Sun et al. (2004) attributed the absorption bands in the FTIR spectrum of sugar cane
bagasse as follows: the adsorption band at 3420 cm -1 is due to the stretching of C-H
groups, that of 2900 cm -1 to the C-H stretching, and that at 1745 cm -1 is assigned as the
C=O ester band. The band at 1639 cm -1 is attributed to the bending mode of the adsorbed
water, that at 1428 cm -1 as CH 2 bending and that at 1328 cm -1 as from C-C and C-O
skeletal vibrations. The C-O-C pyranose ring skeletal vibrations occurs in the region 1076-
1023 cm -1 . The peak at 903 cm -1 originates from β-glycosidic linkages between glucose
units in cellulose. In their study of accelerated ageing of paper under controlled
conditions, Qojewska et al. (2005) also pointed out that the bending vibration band at 1640
cm -1 in the FTIR spectrum is a good indicator of bound water. From Fig 3.23, the presence
of this peak is well pronounced, and could perhaps provide another way of quantitatively
determining the bound water in fibres.
All the electron scanning micrographs showed normal wood tissues such as parenchyma
and wood fibres, and no difference was detected in the fibres of dry leaf, green leaf, rind,
stalk and top (Fig 3.24a-f). Stalk pith (Fig 3.24f) appears to be different, it is more flaky
and has higher surface area than other components.
3.6 CONCLUSIONS
The sugar cane plant of four cane varieties and of three ages has been successfully
separated into fibres of its component parts by means of a simple method specially
developed for the purpose. The use of a 1.18 mm sieve ensures complete separation of
fibres from pith, of which the ratio gives an indication of the milling quality of the cane
variety.
The four cane varieties under study show fibre/pith ratio approaching to one, indicating
good millability. The addition of extraneous matter to clean cane increases the fibre % cane
to the same extent as predicted by the linear equation presented in Fig 2.9 of Chapter 2.
The Brix-free water of the cane component parts will be discussed in Chapter 4 and their
sorption properties in Chapters 5 and 6.
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