A single fibril contains many microfibrils which, when examined with an electron microscope, have a diameter of approximately 100 per microfibril. Microfibrils contain micelles, which are separated into crystalline and amorphous segments. Physical and chemical properties of silk 1. The bave specific gravity on average of sericin and fibroin measures from 1.32 to 1.40. Tenacity and elongation Tenacity indicates the quantity of weight a given fibre can support before breaking.
Degummed silk has greater tenacity than raw silk.
Elongation defines the length to which a fibre may be stretched before breaking. Raw silk has an elongation of 18 to 23 percent of its original length. Excess moisture increases the elongation of silk, but decreases its tenacity. Hygroscopic nature Moisture content and humidity are of critical importance to commercial silk production. Figure 4 illustrates the pattern of moisture regain where a hysteresis exists between the adsorption and desorption curves.