engleski

Mechanical Properties of the Silk Degummed with Citric Acid and Ultrasound

Silk, called the “Queen of fibers”, is a continuous protein fiber produced by silk-worm to form its cocoon. Raw silk fiber obtained by unwinding the cocoons of the silkworm Bombyx mori requires a great deal of handling and processing, which makes it one of the most expensive fibers. Because of the presence of seri-cin, raw silk is rough, hard, brittle, rugged and without lustre. Nowadays, several degumming processes are developed such as extraction with water, boiling off in soap or with alkalis, enzymatic degumming, and degumming in boiling acidic so-lutions. The recommended standard method of degumming is based on Mar-seilles soap, which is very expensive. Recently, acid agents with the purpose to enhance the physical properties of silk replace soap. The action of organic acid is generally milder and less aggressive than the action of alkali. The advantages of citric acid over others of the organic acids are its low cost, proven lack of toxicity, and ready availability. The aim of this paper is to investigate the influence of citric acid and ultrasound on silk degumming. For this purpose, silk fibers were degummed by the classic procedure, and with different concentrations of citric ac-id (15% and 30%), with and without ultrasound. The efficiency of the degumming was determined by measuring degumming ration and mechanical properties (fineness, tenacity and elongation at break) of untreated and treated silk yarn.

Silk degumming, citric acid, ultrasound, properties

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