Wool Fiber - Chemical Composition of Wool

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Wool is a animal fiber of outstanding importance. It is a protein fiber collecting from fur of sheep. This protein fiber consists of C, H, O, N, S etc. Wool is very fine, elastic fiber. Hair of some animals fibers can be considered as textile fiber but wool has special features which distinguish it from other hairs but which renders it supremely valuable as a textile fiber.  These differences are of a physical nature and the basic tissues and chemical structure of all animal hairs, including wool, are similar. 

The wool fiber is complex in structure and composed essentially of three tissues, the cuticle, the cortex and the medulla. Each of these, however is further subdivided by tissue differentiation. A purely diagrammatic illustration of the structure of a non-medullate fiber has shown in image.

The epi-cuticle and exo-cuticles of wool contain a high proportion of sulpher with many cystine cross linkages giving them a high measure of resistance to biological and chemical attack. The endo-cuticle of the other hand is somewhat less resistant. There are inter-cellular membranes which act as a concent holding the cuticle to the adjacent tissues. It is seen from the structural image that the cortical cells are composed of macro-fibrils, each of which contain a number of micro-fibrils lying parallel with each other.

Chemical Composition of Wool:

Component	Percentage
Keratin	33%
Dirt	26%
Suint	28%
Fat	12%
Mineral Matters	1%
Total	100%

Wool is protein fiber thus it contain keratin as a protein. This fiber contains unnecessary substances up to 70 percent in its chemical constituents. The protein substances of wool keratin composed of the C, H, O, N, S with the following percentage.

Composition of Keratin:

Component	Percentage
Carbon	50%
Hydrogen	12%
Oxygen	10%
Nitrogen	25%
Sulpher	3%
Total	100%