Lynne Wong's PhD thesis

5.4.3 Other woody fibre from flax, hemp and reed canary grass
Increased awareness of sustainable production has led to the search for new
environmentally friendly products. Natural fibre from flax, hemp and reed canary grass
are alternatives that can replace synthetic fibres (e.g. carbon, glass and polyester fibres) in
many industrial applications; in addition, they are produced from renewable materials and
can be degraded biologically after use. A deeper knowledge of the adsorption
characteristics of fibre from flax, hemp and reed canary grass was therefore essential in the
management of harvest and post-harvest operations, as well as in the improvement of
quality control during storage.
Fibre from flax, hemp and reed canary grass was studied by Nilsson et al. (2005). The
plant material was cut in lengths of about 200 mm and placed on perforated trays in an
oven at 50 °C to dry to about 5 – 7% moisture. The trays were then placed in climate
chambers connected to air-conditioning units, in which the temperature and relative
humidity were controlled. Experiments were carried out at 5, 15 and 25 °C over a range of
relative humidities from 35 – 90%. When equilibrium was reached, the EMC of the
samples was determined by oven drying at 105 °C for 24 hours.
Five commonly used isotherm models, namely the modified Henderson, the modified
Chung-Pfost, the modified Halsey, the modified Oswin and the modified GAB models
were examined. The modified Halsey model was best for predicting the EMC of un-retted
flax and spring-harvested reed canary grass, the modified Oswin model for dew-retted flax
and un-retted hemp, while the modified Chung-Pfost was best for frost-retted hemp.
5.4.4 Fibre from corn stover components
Igathinathane et al. (2005) determined the EMC and equilibrium relative humidity of corn
leaf, stalk skin and stalk pith of corn stover, which is the aboveground components of the
corn plant minus grain and cob. They used a static gravimetric method at 10, 20, 25, 30,
35 and 40 °C and at ten equilibrium relative humidity values ranging from 0.11 to 0.98
obtained from saturated salt solutions. The results showed that corn stover components
followed a type II isotherm. The experimental data were fitted with the isotherm models of
Henderson, modified Henderson, Chung-Pfost, modified Chung-Pfost, Halsey, modified
Halsey, Oswin, modified Oswin and GAB. The modified Oswin followed by the modified
Halsey model produced the best fit for the corn stover components.
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