Silk

Silk is a natural protein fibre which can be woven into textiles. Silks are produced by several insects, but generally only the silk of moth caterpillars has been used for textile manufacturing. Silk produced by the silkworm, Bombyx mori, produces the best known silk. It feeds on mulberry leave and produces liquid silk which hardens into filaments to form its cocoon. The larva is then killed, and heat is used to soften the hardened filaments so they can be unwound. silk is mainly produced in different parts of Asia, namely China, India, Thailand and parts of Ancient Mediterranean, Middle East, North America, Malaysia, Vietnam.

Silk fibers from the Bombyx mori silkworm have a triangular cross section with rounded corners, 5-10 μm wide. The fibroin-heavy chain is composed mostly of beta-sheets, due to a 59-mer amino acid repeat sequence with some variations.[38] The flat surfaces of the fibrils reflect light at many angles, giving silk a natural shine. Silk has a smooth, soft texture that is not slippery, unlike many fibres. Silk is one of the strongest natural fibers but loses up to 20% of its strength when wet. It has a good moisture regain of 11%. Its elasticity is moderate to poor: if elongated even a small amount, it remains stretched. It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty.

It is often used for clothing such as shirts, ties, blouses, formal dresses, high fashion clothes, lining, pajamas, robes, dress suits, sun dresses and Eastern folk costumes. Silk’s attractive luster and drape makes it suitable for many furnishing applications. It is used for upholstery, wall coverings, window treatments (if blended with another fiber), rugs, bedding and wall hangings While on the decline now, due to artificial fibers, silk has had many industrial and commercial uses, such as in parachutes, bicycle tires, comforter filling and artillery gunpowder bags. It is also being used as surgical sutures – silk does not cause inflammatory reactions and is absorbed or degraded after wounds heal.

Other promising medical uses are as biodegradable micro tubes for repair of blood vessels, and as molded inserts for bone, cartilage and teeth reconstruction.

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