Technical Tests for Fiber Identification

Technical Tests for Fiber Identification
 
Fiber Analysis: Qualitative
Scope: Describe physical, chemical, and microscopical techniques for identifying fibers in raw form or taken from yarn or fabrics.

• Fiber specimens are subjected to a variety of selected tests to determine generic class or specific type
• Visual and microscopical examination
• Burning test
• Solubility
• Stain Tests

 
Technical Tests for Fiber Identification

There are two types of methods that are used for identifying different fibers - the nontechnical tests and the technical tests. The nontechnical tests include the feeling test and the burn test. The technical tests include microscope test and chemical test. The technical tests for fiber identification are carried out in laboratories and require technical knowledge and skills. As such, they are much more reliable methods for testing end product as compared to the non technical tests.
 
Natural fibers have their own peculiar structures, spots, lines and other marks that help in identifying them. Following are some examples of natural fibers and how they look like under a microscope: 

Cotton: The cotton fiber is a single elongated cell. Under a microscope, it looks like flat, spirally twisted ribbonlike tube with rough granular surface. However, mercerized cotton doesn't have natural twist. The finishing process makes them swollen, straight, smooth and round with a shining surface.

Linen: Linen fiber, under a microscope, looks like having multiple sided cylindrical filaments with fine pointed edges. The filaments show nodes at intervals. It, in fact, looks like a bamboo stick having joints that results into a little unevenness.

Wool: Wool fiber has irregular, roughly cylindrical, multi cellular structure with tapered ends. Under a microscope, three basic layers are shown- epidermis (outer layer), cortex (middle layer) and medulla (inner layer). Medulla is seen only in coarse and medium wool fibers and that too under a highly powerful microscope. 

Silk: Raw silk fiber, composed of two filaments, has elliptical shape under the microscope. The two fine and lustrous filaments are shown clearly looking like transparent rods with triangular shape. Wild silk or tussah fiber has different appearance than the cultivated silk. It is flattened, coarse, thick and broader fiber having fine, wavy lines all across its surface whereas cultivated silk is narrower fiber with no marks on it.

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