3. 1. Cotton
Syn: raw cotton, purified cotton,
absorbent cotton, surgical cotton
Source: epidermal trichomes or hairs of the seeds of the
cutivated species of the Gossypium species like
Gossipium herbaaccurrc, Gossipium barbadense
Purified or absorbent cotton: consists of trichomes but
freed from fatty matter and adhering impurities,
bleached & sterilized
GS: Commercially in India, US, Egypt
Constituents: raw cotton: 90% cellulose & 7-8% moisture,
wax, fat and remains of protoplasm
While purified-absorbent cotton-entirely cellulose with
Plant after flowering, bears fruits known as capsule,
fruits are 3-5 celled
Each capsule contain numerous seeds
Seeds covered with the hairs are known as bolls.
The bolls are collected, dried and then taken to
ginning press, wherein trichome are separated
Various devices are used to separate the hairs.
The short & long hairs are separated from each
The hairs with short length are known as linters and
are used for the manufacture of the absorbent
Long hairs are used for preparation of cloth.
The raw cotton is obtained by this way is full of
impurities like wax, fat, coloring matter, vegetable
It is processed to get rid of most of the impurities.
It is taken to the machine known as cotton opener and
followed by treatment with dilute soda ash solution
under pressure for about 10-15 hours.
The wax, fatty material and coloring matter are
removed by this treatment.
It is then washed with water and treated with suitable
It is again washed with water, dried and carded into
Finally packed in wrappers and sterilized by means of
Color: white due to bleaching, slightly off white if
Size: 2.5-4.5 cm I length and 25-35 micron in diameter
Free from pieces of leaves, seed coat, foreign matter
Soak cotton fibre in iodine water & dry add few ml of
80% H2SO4, trichome assume purplish-blue or bluishgreen color
Ammonical copper oxide solution (cuoxam reagent)
dissolves raw cotton fibres with the formation of
balloons, while absorbent cotton dissolves completely
with uniform swelling.
Cotton is insoluble in dilute sodium hydroxide solution
and HCl (distinction from silk)
Cotton is soluble in 55% H2SO4
Absorbent cotton: absorbs blood, mucus, pus and
prevents the wound from infections.
Bacterial infection makes cotton friable & brittle
Should be wrapped in wrappers so as to prevent
the dust and microbial contamination.
Heat and long storage, makes absorbent cotton,
8. 2. Jute
Source: fibres of the stem of various
species of Corchorus olitorius, C.capsularis
GS: West bengal where loamy soil with pH 6-8
Constituents: 53% cellulose, 20% hemicellulose, and
Color: Yellowish brown
Middle lamella is highly lignified and gives red color
with phloroglucinol & conc. HCl
Manufacture of stupa, padding splints, filtering &
straining medium , manufacture of coarse gunny bags
9. 3. Silk
fibres obatined from cocoons of
Bombyx mori (mulberry silkworm)
Family: Bombycidae, Order: Lepidoptera
GS: Japan, Italy, China, France, India
Constituents: protein known as fibroin, fibroin on
hydrolysis amino acid glycine + alanine
Color: usually Yellowish threads
Since it does not contain, sulfur, test with lead
acetate is negative.
Insoluble in water and alcohol
Soluble in cuoxam solution, 66%H2SO4, Conc. HCl
Uses: speical types of sutures, sieves and ligatures
The larvae of the silkworm produce silk fibroin fibres
from the glands in their mouth
This fibroin gets united with a gum like secretion
known as sericin and forms cocoon
These cocoons are not allowed to grow further into
an insect, but are heated to 60-80 degree C by
exposing them to steam.
The exposed cocoons are put into hot water to
dissolve the gum and to separate fibres
12. 4. Wool
Source: fibres obatined from fleece
sheep Ovis aries
Family: Bovidae, Order: Ungulata
GS: Australia, Russia, Argetia, US and India
Constituents: sulphur containg protein known as keratin,
rich in amino acid cystine.
When lead acetate is added to a solution wool in
NaOH, black ppt is formed due to high sulphur content.
Insoluble in cuoxam solution, 66%H2SO4, Conc. HCl
Uses: filtering & straining medium, manufacture of
dressing like domette and crepe bandages and
The hairs forming on the fleece of the sheep are
removed at shearing time.
They are then processed to remove the wool fat
The clean & de-fatted wool is subjected to
bleaching, washed again and dried.
When observed under high power, wool shows
cuticle, cortex and medulla.
14. 5. Rayon
Syn: Regenerated cellulose, Viscose rayon
Source: artificial fibres composed of
regenerated cellulose in which substituents have replaced NMT 15% of
hydrogen of –OH group. Now, it is exclusively prepared by the viscose
The cellulose of coniferous wood in the form of pulp is processed to give
The pulp contains 80-90% of cellulose and hemicellulose.
The cellulose is treated with NaOH to get Sodium cellulose.
It is further treated with CS2 & NaOH to produce viscose solution of
sodium cellulose xanthate.
After ripening, this solution is forced through the fine nozzles into the
bath of sodium sulphate and H2SO4 to give continuous filaments.
The filaments are drawn together to form the yarn.
The yarn is desulphurized, bleached, washed twisted and then dried.
Rayon contain about 10% moisture and does not loose absorbency on
storage like cottom.
Making fabrics, preparation of surgical dressing, viscose rayon &
15. 6. Nylon
is the polymer of adipic acid and
The fibres are highly lustrous to dull, white or
When applied to flame, the fibre melts with
formation of bead.
It is soluble in 5M HCl and insoluble in acetone.
It is soluble in 90% formic acid & phenol (90%)
which distinguishes it from fibres of biological origin.
Filter clothes, sieves and non-absorbable sutures.
16. 7. Glass fibre
The fibres consists of sand (silica),
mixed with oxides of aluminium, calcium, boron
They are unaffected by all usual reagents used in
identification of fibres.
They melt at high temperature and form a
They are used in filer fabrics for insulation and
17. 8. Asbestos
Contains mainly hydrated magnesium
Rock asbestos is white, yellow or green in color.
It is highly refractive and also do not fuse when
Insoluble in warm HCl
Preparation of filtering medium & for bacterial
19. 1. Kaolin
China clay, Kaolinum proderesum
Source: purified native hydrated aluminium silicate
free from gritty particles.
Preparation: by powdering native kaolin, elutriating
and collecting the fraction, which complies with
the requirement s of particle size. The native clay is
derived from decomposition of the feldspr
(Potassium aluminosilicate) or granite rock ad
contains silica (47%), alumina (40%) and water
GS: South easter US, England, France, India
1 Heavy: purified hydrated aluminium silicate powdered so as
to make free from gritty particles by elutriation.
2 Light: identical to heavy kaolin, but is limited tp certain
particle size and contains suitable dispersing agent.
3. Natural: native hydrated aluminium silicate free ftom gritty
particles, but devoid of dispersing agent.
Color: normally white but often gets tinged to grey, yellow or
brown due to impurities.
Odor: odorless, size: 10-60 micron, fusion point: 1700-1800
Solubility: insoluble in water, mineral acids.
not affected by HCl but decomposed by conc. H2SO4 after
prolonged boiling, absorb small amount of water.
Use: adsorbent as oral administration, treatment of enteritis,
dysentery, alkaloid-food poisoning, dusting powder, clarifying
agent during filtration.
Light: pharmaceutical preparation
Heavy: kaolin poultice, filler in paper, rubber, ceramics,
cement, fertilizer industries, anticaking preparation, cosmetics,
insecticides, paints & source of alumina.
21. 2. Chalk
Syn: creta, paris white, whiting
Source: native form of CaCO3, free from most of the
impurities by elutriations. It contains NLT 97% w/w of
CaCO3, when dried at 100 degree C.
Preparation: mined in open quarries, pulverized by
elutriation. The water is removed and the insoluble chalk
settle forming flak cakes, known as whiting. It is purified
further for pharmaceutical use.
Description: colorless, odorless, white earthy and soft to
touch. It is amorphous and insoluble in water. When
treated with acids, it effervesces.
Constituents: 96% CaCO3, 0.5% MgCO3, 0.5-1% silica,
traces of iron,manganese and aluminium oxides.
& dietary supplement, dusting powder,
anti-diarrhoeal, face powder, abrasive in tooth
powders and tooth paste, manufacture of
antibiotics and other pharmaceuticals.
Precipitated Chalk: absence of foraminiferous shells
as it is obtained from chemical reactions.
Prepared chalk has various shape and size of
foraminiferous shells as observed under microscope
using cresol as mountant.
23. 3. Diatomite
Syn: Kieselguhr, Celite super cel, Industrial earth
Source: natural diatomaceous earth consisting of siliceous of
fossil, Family: Bacillariaceae
Purified by treating it with dil HCl and washing with water and
GS: West Germany, Denmark, Algeria, Kenya, US, UK
Preparation: mined in open quarries, where in large blocks
containing moisture to the extent of 30-40% are arranged
and dried in air, the blocks containing 5-10% of moisture are
then pulverized to produce fine powder & subsequently
graded. The powder is then subjected to acid treatment,
washed thoroughly with water and finally dried.
Description: brownish-grey to white colored light powder,
odorless, tasteless. Very smooth and adheres to the skin by
rubbing. It is not slippery. Absorb moisture, but does not swell
when mounted in cresol. It is invisible in polarised light with
crossed nicols. Diatoms vary in size and exhibit two shapes,
elongated and circular or triangular known as discoid.
silica, 1-5% aluminium oxide, 1.5% Calcium
oxide, 1.5% Magnesium oxide, 5% iron oxide.
Filter aid, clarification and decolorization of liquids,
manufacture of tooth powder, face powder, nail
polish, filter candle preparation
25. 4. Bentonite
Source: natural colloidal hydrated aluminium silicate
(clay) found in many parts of the world.
GS: Italy, Canada, South Africa, South-East US
The finest variety comes from Benton in US and hence
name is bentonite.
Preparation: found in the form of soapy lumps in the
mines. Lumps are steam dried followed pulverization
Description: cream to pale buff yellowish or pinkish tint
colored very fine powder, free from grittiness, odorless,
earthy in taste.
Insoluble in water & organic solvents, when added to
water, It swells about 12 times of its volume.
montmorillonite (Al2O3.4SiO2.H2O), 60% SiO2,
20% Al2O3, 2-3% MgOxide, 3% Ferric Oxide
When mounted in 0.1% methylene blue in 95%
alcohol, deep-blue color.
When mounted in 0.1% safranine in 70% alcohol,
permanent deep red color.
Suspending & emulsifying agent, base for plaster,
base for cream-lipstick-depilatories in cosmetics
27. 5. Talc
Syn: French Talk, Talcum, Soap stone, Purified talc
Source: natural hydrated magnesium silicate. It is
purified by boiling with dilute HCl, decanting the liquid,
washing the residue several times with water & drying at
110 degree C.
GS: France, NY, Italy & India.
Description: very fine white or greyish-white powder
without order and taste. It is free of gritty particles,
greasy to touch and adheres to skin. Talc is insoluble in
water, dilute acids and alkali hydroxides.
It is fine variety of steatite occuring as massibe mineral
with pearly white lusture and non-plastic thusm
distinguished from mica.
Specification: density: 2.2-2.8
Hydrated magnesium silicate, 1-2% Iron oxide, traces of
Color of talc is due to iron oxide content.
Chemical Test: fuse about 0.5 g talc with 0.2 g of anhydrous
Na2CO3, K2CO3 in platinum crucible. Dissolve the fused
mixture into 50 ml of water and to it add HCl to it until it
ceases to effervescence. Add little more acid and
evaporate the contents to dryness on water bath. Cool it,
dissolve in 20 ml of water, boil and filter. To the filtrate, add
about 2 g of Ammonium chloride and 5 ml of ammonia
solution. If any precipitate is formed remove it filtration. To the
filtrate, add sodium phosphate, white crystalline precipitate
of magnesium ammonium carbonate will be formed.
Filter aid for filtration and clarification of cloudy liquids, as
lubricant in preparations of pills and tablets and as dusting
It is used in paint & varnish industry, filter for paper and heat
and electric insulator.