Environmental Engineering Reference
In-Depth Information
The fibre is most often spun into thread and used to make textiles, making cotton
the most widely used natural-fibre fabric in clothing today.
The structure of cotton fibres is similar to that of the secondary walls (S1, S2 and
S3) of a wood cell. Cotton comprises 98% cellulose with almost no lignin (no mid-
dle lamella gathering all the fibres together). The natural wax on the surface of the
fibres is very useful for threading as it lubricates their contact with the machines,
minimising fibre damage. The long fibres are used for textile applications while
the shorter fibres (linters) of cotton are used as a source of high-quality cellulose
for biomaterials. Cotton is used for the chemical transformation of cellulose
(regeneration, esters and ethers, see Section 6.3.1) for which high purity is required.
6.2.3.2
Linen or Flax Fibre
As used today, the word 'linen' is descriptive of a class of woven textiles used in
homes. Linens were manufactured almost exclusively using fibres from the flax
plant Linum usitatisimum. Today flax is a prestigious, expensive fibre and only
produced in small quantities. Flax fibres can be identified by their typical nodes,
which account for the flexibility and texture of the fabric. The cross-section of the
fibre is made up of irregular polygonal shapes, which contribute to the coarse
texture of the fabric. When adequately prepared, linen has the ability to absorb
and lose water rapidly. It can gain up to 20% moisture without feeling damp.
Linen uses range from bed and bath fabrics, home and commercial furnishing
items (wallpaper/wall coverings, upholstery, support for oil painting, etc), pres-
tigious clothing, to industrial products (luggage, canvases, sewing thread, etc).
Linen is preferred to cotton for its strength, durability and archival integrity.
6.2.3.3
Jute
Jute is a long, soft, shiny vegetal fibre that can be spun into coarse, strong threads.
It is produced from plants in the genus Corchorus. Jute is one of the cheapest
natural fibres, and is second only to cotton in amount produced and variety of
uses. It can be grown in 4-6 months. The mechanical properties of jute hurd (inner
woody core or parenchyma of the jute stem) are a cross between those of textile
fibre and wood; it therefore has good potential to fight deforestation. Jute is the
second most important vegetal fibre after cotton not only for cultivation but also for
various other uses; for example, jute is used to make coarse cloth for wrapping bales
and sacks. The fibres are also woven into curtains, chair coverings, carpets, area
rugs and backing for linoleum.
While synthetic materials are replacing jute in many of these uses, synthetics
would be unsuitable for some applications which depend upon the biodegradable
nature of jute. Examples of such uses include: containers for planting young trees,
which can be planted directly with the container without disturbing the roots; geo-
textiles, which is a lightly woven fabric made from natural fibres that is used for
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