Lynne Wong's PhD thesis

Table 3.2. Fibrous physical composition of bagasse (Villavicencio, 1974).
Mass/%
Fibres suitable for paper-making
True fibres
Vessel segments
55
20
Pith
Parenchyma cells
Other non-fibrous components, e.g. nodes
20
5
According to Paturau (1989), the true fibre and the pith have almost the same chemical
composition, but their structure differs widely. The true fibres have a fairly high ratio of
length-to-diameter (approximately 70), and a relatively high coefficient of expansion and
contraction upon wetting and subsequent drying. This results in close bonding of one fibre
with another and accounts for the strength, cohesiveness and the ability to become matted
when subjected to pulping processes.
The pith cells are of irregular size and shape, with a length-to-diameter ratio of about 5.
They are characterised by their absorbent properties. They do not bond together and so
tend to weaken any pulp in which they are incorporated and, further, prevent its rapid
drying. However, they can absorb many times their mass of liquid.
3.2 THE CHOICE OF SUGAR CANE SAMPLES FOR FIBRE
EXTRACTION
In this work, in order to obtain cane samples of different varieties and of differing ages in
the same environment, the materials were removed “randomly” from the experimental
rows of maturity testing trials of recently released cane varieties. These trials were
established by the Plant Physiology Department of the MSIRI in various agro-climatic
environments of the island, having as treatments three harvest dates and ten cane varieties.
As cane harvesting in Mauritius usually starts at the beginning of June and ends in
November, three harvest dates were included in these trials: early, middle and late, i.e.
June, September and November respectively, apart from the cane varieties that are being
compared.
72