Physical properties:
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Silk fibers have a triangular cross section with
rounded corners and allows light to hit at different angles and it has a
natural shine.
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The denier becomes when wet then 4.0g/d and when
dry then 4.5g/d.
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Smooth, soft texture that is not slippery.
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Good moisture regain of about 11%
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Strongest natural fibers and up to 20% losses of
its strength when wet.
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Poor elasticity.
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The ironing temperature is moderate.
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Silk is sensitive to light than other natural
fibers.
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Yellowing of the fiber is generally accompanied
by photo degradation that is mainly occurred due to action of UV radition of
light.
Chemical properties:
Acid: Silk is readily decomposes by hot
concentrated acids. The degree of hydrolysis is much greater with acid than
with alkali & is pH dependent. There is no harmful of weak and
cold hydrofluoric acid. Dilute organic acids contain little effect on silk at
room temperature.
Alkali: Dilute alkali at room temperature
does not cause any considerable chemical and structural damage of silk, but the
luster of the fiber may be decreased depending on the exposure time. Caustic
soda, when it is hot and strong, dissolves the silk fiber.
Oxidizing agent: Silk fibroin is not
severely affected by H2O2 solution.
The action of chlorine solution on the silk
fibroin is more harmful than hypochlorite solution.
Reducing agent: The
reducing agents that are commonly found in use in textile processing such as
hyposulphite, sulfurous acids and their salts do no exercise any constructed
action on the silk fiber.