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SYNTHETIC FIBRES AND

MINERAL FIBRES

NANDHINI.

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There are two types of fibre – One which are obtained from natural sources and other which are man-made.

Fibres which are obtained from natural sources are called natural fibres. For example – cotton, silk, wool, etc.

Fibres which are man-made are called man-made or synthetic fibres. For example –rayon, nylon, Polyester, etc

TYPES OF FIBRES

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Man-made – Synthetic Fibres

• Fibers made by chemical synthesis are often called synthetic fibers.

• Examples: Polyester Nylon

Polyester

Nylon

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Man-made – Regenerated Fibres

Fibres regenerated from natural polymer sources.

Examples: Rayon Acetate

Acetate

Rayon

NYLON5

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Nylon is the polymer of adipic acid and hexamethylene diamide.

Nylon is synthesized from coal, water and air. The fibres are highly lustrous to dull .They are very strong when dry or wet.

Identification test:

It is soluble in 5M hydrochloric acid and insoluble in acetone.

It is soluble in 90% formic acid and 90 % phenol.

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Uses:

Nylon is used for filter cloths, sieves and

non-absorbable sutures

It is used for making nylon syringes

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NYLON SIEVES

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RAYON

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Synonyms Regenerated cellulose,viscose rayon.

Source: It is an artificial fibre.

The cellulose of coniferous

wood in the form of pulp is

processed to give viscous rayon.

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WOOD PULP ↓ THE PULP CONTAINS 80 - 90% CELLULOSE

AND HEMICELLULOSE ↓IT IS TREATED WITH SODIUM HYDROXIDE TO

GET SODIUM CELLULOSATE ↓FURTHER TREATED WITH CARBON DISULPHIDE

AND SODIUM HYDROXIDE ↓

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VISCOUS SOLUTION OF SODIUM CELLULOSE XANTHATE ↓

AFTER RIPENING ,THIS SOLUTION IS FORCED THROUGH THE FINE NOZZLES INTO THE BATH

OF SODIUM SULPHATE AND SULPURIC ACID ↓

THE FILAMENTS ARE DRAWN TOGETHER TO FORM YARN.

↓

THE YARN IS DESULPHURIZED ,BLEACHED ,WASHED TWISTED AND THEN DRIED

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Identification test :

With N/50 iodine and 80% sulphuric acid, it gives a blue colour

It dissolves in 60% cold sulpuric acid.

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Uses:It is mainly used for making

fabrics ,preparation of surgical

dressing and viscose rayon

absorbent wool.

Rayon

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RAYON SWAB RAYON WIPER

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ALGINATE FIBRES:

Source: Regenerated fibres prepared from Sodium alginate of seaweed.

Preparation : An aqueous solution of sodium

alginate is prepared .It is pumped through a spinneret

immersed in a bath containing calcium chloride .

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The water insoluble calcium alginate is precipitated as a continuous filament.

It is washed and dried .

Constituents: Alginate fibres contain calcium salts of long chain molecules of alginic acid

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Identification tests: It is insoluble in 60% sulpuric

acid.

It is soluble in 5 % sodium citrate

solution

With N/50 iodine and sulpuric

acid, a brownish red colour is

produced .

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Uses: Absorbable haemostatic

dressings.

Calcium alginate wool is used

to swab for pathological work and

bacteriological examination

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Terylene

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It is obtained by condensation of ethylene glycol and terephthalic acid Identification test:

Retains its form when boiled with 90% phosphoric acid for 1 minute.

Uses:It is being used for artificial

grafts and also as non –absorbable suture.

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Characteristic of Synthetic Fibres

Synthetic fibres are cheaper than natural

fibre.

Fibres are stronger than natural fibre.

It is easy to maintain the synthetic fibres.

It is easy to wash the synthetic fabrics.

Synthetic fabrics are dried up in less time.

Synthetic fibres are readily available.

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MINERAL FIBRES

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GLASS FIBRES: The fibres consists of silica

mixed with oxides of aluminium,

calcium, boron and magnesium .

They melt at high temperature

and form a transparent layer.

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Glass fibre for splinting teeth

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ASBESTOS :It contains mainly hydrated

magnesium silicates.

Rock asbestos is white ,yellow

or green in colour .

It is highly refractive and do

not fuse when heated

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Uses:It is used for preparation of a

filtering medium and for bacterial

filters.

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