About Wool fibre (part-1) ~ Textile Notes

WOOL(Part-1)

#History

◆Wool is a type of fibre which obtained from sheep and other animal.

◆Wool in felted state was probably oldest fibre known to man.

◆History shows clearly that Mesopotamia is the birth place of the wool.

◆Manufacturing of woollen cloth was an important industry in Mesopotamia.

◆From there, this knowledge spread to adjoining areas and ancient Egyptians, Babylonians, Greeks and Hebrews practised hand spinning and weaving in home.

◆Thus wool industry developed as a household craft all over the world.

◆During the early Christian Era the finest woollen materials came from Baghdad, Damascus and other cities of the Turkish Empire.

◆The middle ages of the woollen industry flourished in the Italian cities such as Venice and Florans, from were it spread to Netherlands, Belgium and England.

◆It then was take to America by a Spaniards. Some sheep were takes from England to Australia where there were no native sheep.

◆Wool flourished very well in Australia, which has become a leading wool producer followed by China, Us, New Zealand.

◆Animals grow hair on their body from carbon, hydrogen, oxygen, nitrogen, sulphur etc. These are obtained by animals from the food they eat and air they breath.

#Physical structure of wool

◆The wool fibre generally appears as a circular cylinder that tapers from the root to the tip. It has a spirally crimped form. When viewed through the microscope, wool fibre shows four distinct regions. They are:-
(a) the outer sheat or epicuticle,
(b) the scale cell layer, cuticle
(c) the cortex, and
(d) the medulla (in coarse world only)

(a) Epicuticle:-

◆The outer sheath consists of the non-protein part of the fibre.

◆It is a thin, water -repellent membrane.

◆It has, however, tiny microscopic pores, through which water vapour may penetrate into the internal structure of the fibre.

◆Thus the outer sheath helps wool fabrics to absorb water vapour from the human body without feeling damp, and release it into the air.

(b) Cuticle:-

◆Underneath the epicuticle, at the surface, there are cuticle or scale-like cells.

◆These thin scales are hard and of horny consistency. These overlap and protrude for about one-third of their length, the end being directed towards the tip of the fibre.

◆The outermost layer of these scales is a tough membran known as the epicuticle.

◆Beneath this the exocuticle is situated and the inner most layer described as the endocuticle.

◆These cause a special directional frictional effect that has a very important influence on the
frictional behaviour of wool fibres.

(c) Cortex:-

◆The bulk of the fibre is formed of the cortical cells or cortex, and it is enclosed by the cuticle.

◆Within the cortex there is a fibrillar structure. The cortical cells are 100-200 microns in length and 2-5 microns wide.

◆The tensíle strength, elastic properties and the natural colour of the wool are determined mainly by the nature of the cortical cells.

◆The cortex of the wool fibre has been shown to have a bilaterial structure; one side is called the paracortex and the other orthocortex.

◆The chemical structure of the proteins in the two sections is thought to be different.

◆The paracortex is more stable and is less accessible to dyes than the orthocortex.

◆This bilateral structure gives the fibre a crimped form that is in phase with the mutual twisting of the two sections.

◆It appears that distribution of the two varieties is such as to divide the cortex longitudinally into two hemi-cylinders.

(d) medulla:-
◆Many coarse wool fibres have a the center running along the length of the fibre. This hollow space in the centre running along the length of the fibre.

◆This is the medulla and it may be empty or it may be made up of a different type of cell. The medulla is absent in fine wools.

Wool Fibre part-2 link:-https://www.weindians.xyz/2019/10/wool-chemical-structure-wool-fibre-is.html

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Textile Notes