Lynne Wong's PhD thesis

loosen the fibre. The woody core is then broken near the base and the broken pieces
discarded. The fibre is stripped from the core; afterwards, adhering pieces of bark and
broken stick are removed by lashing the stripped fibre on the surface of the water. The
fibre is then washed, wrung dry and sun-dried on horizontal wires or poles. Retting is the
most important step in the production of good quality jute; under-retting or over-retting can
lead to downgrading of the jute fibres produced.
Leaf fibres are usually extracted without recourse to retting. In its simplest form the
extraction is carried out by first beating the leaf to soften the non-fibrous soft tissue, and
then scraping the fibres clean. Sisal leaf is such an example requiring a mechanical device
to clean the fibres (Jarman, 1998). However, some leaves containing high levels of pectins
will require retting as well as chemical treatment.
3.3.2 Methods reported for the sugar cane plant
In an attempt to extract fibres from sugar cane for use as textile fibres, Jhingooree et al.
(2000) applied chemical degumming treatments to the rind section of the sugar cane stalk,
which they boiled in sodium hydroxide solutions of various concentrations (5, 10 and
15%) for a limited period (2, 4 and 5 hours). The fibrous tissues obtained after the
degumming treatment still contained debris from degraded vegetable matter, and required
combing with a hair comb to get rid of the undesirable intercellular gummy matter binding
the fibres together. The combing process could not be carried out too many times as it led
to the breakage of the fibres. They found that the tenacity of the subsequently separated
fibres decreased with increase of the alkali concentration as well as the boiling time.
Instead of cane rind, when whole cane was crushed by a hammer before the treatment of
alkali, a lower concentration of alkali (< 5%) was required to achieve the same results as
with 15% alkali on the rind section. When crushed cane was treated with high
concentrations of alkali, the fibres deteriorated. Softeners and crease-resisting agents were
also applied to the fibres before combing to enable the fibres to swell and become looser.
In so doing, the combing process became easier.
To extract fibres from cane samples, Mangion and Player (1991) processed cane samples
via the use of a wet disintegrator, a Jeffco cutter-grinder and a gyratory-type machine
grinder. In physical appearance, the wet disintegrator and Jeffco cutter grinder materials
were similar, with pith and long fibre in the sample being easily distinguishable and
separable. The mechanical grinder which consisted of agitated concentric steel rings
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