Fibres : Cotton, Hemp, Jute PDF / PPT

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• Classification
• Cotton
• Hemp
• Jute 2


 Tissue composed of Spindle shaped or elongated thick walled
cells with pointed ends, cell walls of which consist of cellulose
and may or may not contain lignin.

 Fibres are developed from single cell, the fibre initial, which
during its development grows rapidly in the axial direction.

 They are unicellular in structure.

 During its growth period, the tips of the elongating cells may
push one another. This process is known as “Gliding growth.” 3 4


1. Microscopical examination

2. Physical test like ignition test

3. Various chemical test are done like

MOLISCH’S TEST: Sample + α-napthol in alcohol and

conc. Sulphuric acid Violet colour- Plant and

regenerated fibres present


Sample + Millon’s reagent + Warm Red colour- Animal
fibres present 5 6


SYNONYM:- Raw cotton or absorbent cotton,
surgical cotton, purified cotton

BIOLOGICAL SOURCE:- Cotton consist of the
epidermal trichomes or hairs of the seeds of
cultivated species of the Gossypium herbaceurre,
G. herbaceum, G. barbadense, G. hirsutum

FAMILY:- Malvaceae 7


Purified or absorbent cotton consist of the
trichomes as mentioned above, but freed from
fatty matter, and adhering impurities. It is also
bleached and sterilized.

Africa, South Africa etc. 8


 Seeds are covered with the hairs are known as Bolls.

 They are collected, dried and taken to ginning press where
trichomes are separated from the seeds.

 Various devices are used to separate the hairs. The short and long
hairs are separated from each other. The hairs with short length
are know as Linters and used for the manufacture of absorbent
cotton while long hairs are used for the preparation of cloth.

 The raw cotton obtained by this way is full of impurities, like
wax, fat, coloring matter, vegetable debris etc. 9


 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 solution or soda ash solution under
pressure for about 10-15 hours.

 The wax, fatty material and coloring matter are removed by this

 It is then washed with water and treated with suitable bleaching

 It is again washed with water, dried and carded into flat sheets.

 It is finally packed in wrappers and sterilized by means of
Gamma radiations. 10


 Size- 2.5 to 4.5 cm in length and 25 to 35μ in diameter.

 Shape- Cylindrical when young, but becomes flattened
and twisted as it matures

 Colour- white (Due to bleaching), Slightly off white if

 Odour- Odourless
 Taste- Tasteless
 Extra features: Appearance is soft, fine, filament like

hairs which are unicellular 11


 The trichomes are unicellular, flattened and ribbon like
with slightly thickened and rounded apex.

 They are tubular and hollow. 12


 90% of cellulose,
 7-8% of moisture,
 0.4% wax, fat, oil,
 0.6% protoplasm and other cell content and 0.2%

 Purified cotton or absorbent cotton is entirely

cellulose with 6-7% of moisture and 0.2-0.3%
ash. 13


1. Specific test for cotton:- Cotton fibres + N/50 iodine
Solution+ dry it + add few ml. of 80% sulfuric acid
Trichomes assume purplish-blue or bluish-green colour
(Distinction from jute, hemp, wool, silk, nylon, alginate
yarn and acetate rayon)

2. Cuoxam test:- Raw cotton fibres + Ammonical copper
oxide solution (cuoxam-reagent) dissolves raw cotton
fibres with formation of balloons, while absorbent
cotton dissolves completely with uniform swelling. 14


3.Cotton + dilute sodium hydroxide solution and HCl
Insoluble (Distinction from silk).

4.Cotton + Cold 80% of sulfuric acid Soluble

Insoluble in cold 60% sulfuric acid, Conc. HCl, 5%
KOH, 90% phenol, cresol, acetone 15


 Filtering medium and surgical dressings.

 Insulating material

 Absorbent cotton absorbs blood, mucus, pus and

 prevents the wounds from infections. 16


 Store in cool place.

 The absorbent cotton should be wrapped in
wrappers so as to prevent the dust and microbial

contamination. 17 18


 Synonyms: Cannabis Indica, Indian hemp, Ganja,
Marihuana, Charas.

 Biological source:

Hemp fibre is obtained from the bast of the plant
Cannabis sativa

 Family: Cannabinaceae 19


 There are broadly three groups of Cannabis
varieties being cultivated today:

1. Varieties primarily cultivated for their fibre,
characterized by long stems and little branching,
called industrial hemp.

2. Varieties grown for seed from which hemp oil is

3. Varieties grown for medicinal or recreational
purposes. 20


 Fibres are obtained by subjecting the stalks to a series of
operations—including retting, drying, and crushing—and a
shaking process

 That completes separation from the woody portion,
releasing the long, fairly straight fibre, or line.

 The fibre strands, usually over 1.8 metres (5.8 feet) long,
are made of individual cylindrical cells with an irregular

 The fibre diameter ranges from 16 to 50 microns.

 The fibre, longer and less flexible, is usually yellowish,
greenish, or a dark brown or gray and, because it is not

easily bleached to sufficiently light shades, is rarely
dyed. 21


 Long, strong and durable, hemp fibres are about
70% cellulose and contain low levels of lignin
(around 8-10%).

 Pectin-2.9%
 Fat-Wax-0.9%
 Mineral-1.8% 22


 Hemp has been used for centuries to make rope, canvas
and paper

 Cloth
 Filter 23 24


 Synonym :- Gunny

 BIOLOGICAL SOURCE: It consists of
phloem fibres from the stem of various species
of the Corchorus; C. capsularis Linn, C.
olitorius Linn, and other species like C.
cunninghamii, C. junodi etc., belonging to

 Family :- Tiliaceae. 25


 Geographical Source :- West Bengal and Assam.

 Description :-
 They are tall, usually annual herbs. Reaching to a

height of 2–4 m, unbranched and if branched it
has only a few side branches.

 The leaves are alternate, simple, lanceolate, 5–15
cm long and a finely serrated or lobed margin.

 The flowers are small (1.5–3 cm in diameter) and
yellow, with five petals;

 The fruit encloses many seeds in the capsule 26


 Retting is the process for the preparation of bast fibres.

This process is done by three methods,

Microbial (orWater),


Mechanical Process.

 The microbial or water retting process is the oldest and the popular
method employed for the breaking of lignin bond present between
parenchyma and sclerenchyma.

 The breaking of this bond facilitates the easy procurement of skin
from its core.

 Then the material is washed dried to release pectin bond which
makes the hard skin to fine thread like fibres.

 The jute fibres are graded according to its colour, strength and fibre

 The fibres are of white to brown and 1–4 m. long 27


Microscopy :-

A thin transverse section of the strand when treated with
phuloroglucinol and HCl, stains the strands deep red,
indicating the presence of lignin. 28


 Cellulose → 50-53%
 Hemi-cellulose → 20%
 Lignin → 12-13%
 Water Soluble matter → 1.5%
 Fat and Wax → 1 % each 29


 It is listed as the second most important vegetable
fibre after cotton.

 Jute is used chiefly to make cloth for wrapping bales
of raw cotton, in the preparation of sacks and coarse

 They are also woven into curtains, chair coverings,

 Hessian cloth very fine threads of jute can be made
into imitation silk and also in the making of paper.

 It is even used in the manufacture of tows, padding
splints, filtering, and straining medium.

 Jute is used for the preparation of coarse bags. 30


Bales of raw
cotton sacks

Hessian cloth Padding splints 31


Thank You 32