2 pages essay on processing of silk and associated health hazards.
Answers
Explanation:
Sericulture, the production of raw silk by means of raising caterpillars (larvae), particularly those of the domesticated silkworm (Bombyx mori).
The production of silk generally involves two processes:
Care of the silkworm from the egg stage through completion of the cocoon.
Production of mulberry trees that provide leaves upon which the worms feed.
The silkworm caterpillar builds its cocoon by producing and surrounding itself with long, continuous fibre, or filament. Liquid secretions from two large glands within the insect emerge from the spinneret, a single exit tube in the head, hardening upon exposure to air and forming twin filaments composed of fibroin, a protein material. The second pair of glands secretes sericin, a gummy substance that cements the two filaments together. Because an emerging moth would break the cocoon filament, the larva is killed in the cocoon by steam or hot air at the chrysalis stage.
Silk is a continuous filament within each cocoon, having a usable length of about 600 to 900 metres (2,000 to 3,000 feet). It is freed by softening the binding sericin and then locating the filament end and unwinding or reeling, the filaments from several cocoons at the same time, sometimes with a slight twist, forming a single strand. Several silk strands, each too thin for most uses, are twisted together to make thicker, stronger yarn in the process called throwing, producing various yarns differing according to the amount and direction of the twist imparted.