Author Topic: Composition & Physical, Chemical, Thermal Properties of Cotton  (Read 9035 times)

Offline Subrata

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Composition & Physical, Chemical, Thermal Properties of Cotton
« on: October 26, 2011, 01:01:27 PM »
Composition:
In the chemical structure of cotton, the maximum portion is cellulose and the rest is composed of different types of dust and wax like materials. The whole chemical construction of cotton can be described as follows:

Cellulose:80-90 %
Waxes & Fats: 0.5-1 %
Proteins: 0-1.5 %
Hemicelluloses & Pectin’s: 4-6 %
Water: 6-8 %
Ash & Mineral Matters:  1-1.8 %


Physical Properties:
Specific gravity: 1.52-1.55
Strength (Tenacity): 3.0 - 4.9 g/d (Cotton is 20% stronger when wet). Fiber elongation is almost linear to the stress imposed
Elasticity: Relatively low
Absorbency and MR%: 7-8% at standard conditions
Birefringence: 0.046
Dielectric constant: 3.9-7.5
Resistivity: Order of 109 ohm/cm3
Micronaire: 2.0 - 6.5 (upland cotton)
Denier: 0.7 - 2.3 (upland cotton)
Length: 0.9 - 1.2 in (upland cotton)
Diameter:  9.77 - 27.26µm
Coefficient of friction: 0.25 (for raw dry cotton, otherwise strongly changes for treated and/or wet fiber)
Breaking Extension: 5-7%
Resiliency: Relatively low
Dimensional Stability: Medium
Abrasion Resistance: Better


Chemical Properties:
Effect of Bleach: Cotton fiber is resistant to bleach & H2O2 , NaOCl , NaClO2 , Ca(OCl)Cl are used as bleaching agents.
Effect of Acid: Cotton fiber is dissolved in high concentrated mineral acid but organic acid cannot dissolve it.
Effect of Alkali: Cotton fiber is resistant to alkali. Scouring is done by using alkali for removing impurities.
Effect of Heat: Cotton fiber burns rapidly in air. It begins to turn yellow after several hours at 120oC and decomposes at 150oC.
Effect of Sunlight: Cotton fiber can absorb heat and energy from sunlight. But excess application of sunlight may degrade the polymer system of fiber as it is attacked by the UV- ray of sunlight.
Effect of Organic Solvent: Cotton fiber is well resistant to most organic solvent.
Dye ability: Reactive, Direct, Vat, Azoic, Mordant Dyes are used to dye cotton fiber. But the best dye for cotton fiber is Reactive Dye.


Thermal Properties:
Cotton requires particular temperature, humidity and possibly ventilation conditions.
Favorable travel temperature range: no lower limit < 25°C
Optimum travel temperature: 20°C
Auto ignition temperature (for oily cotton: 120°C
Glow temperature: 205°C
Fire point: 210°C
Ignition temperature: 407°C

At temperatures > 25°C, cotton dries out, becomes hard and brittle and losses elasticity. Light causes the same deterioration. The optimum temperature for mold development is 25 - 35°C.

Cotton is subject to self-heating/spontaneous combustion. The auto ignition temperature of oily cotton is 120°C.
At temperatures < 0°C there is no risk of wet bales rotting, since this process stops at low temperatures. In some cases, damaged cotton has been placed in intermediate cold storage, so preventing rot.
Every hold should be equipped with means for measuring temperature. Measurements must be performed and recorded daily.
« Last Edit: October 26, 2011, 01:07:44 PM by Subrata »

Offline Suha

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #1 on: October 26, 2011, 01:22:13 PM »
Good information about cotton fiber.
Engr. Md. Mahfuzur Rahman
Asst. Professor
Department of Textile Engineering
Daffodil International University

Offline Tanvir Ahmed Chowdhury

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #2 on: October 26, 2011, 08:07:12 PM »
Good post.
Tanvir Ahmed Chowdhury

Assistant Professor
Department of Textile Engineering
Faculty of Engineering
Daffodil International University

Offline baset

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #3 on: October 26, 2011, 08:11:52 PM »
Cotton, as a natural cellulosic fiber, has a lot of characteristics, such as;

    * Comfortable Soft hand
    * Good absorbency
    * Color retention
    * Prints well
    * Machine-washable
    * Dry-cleanable
    * Good strength
    * Drapes well
    * Easy to handle and sew
M.A.BASET
Assistant Professor,
Department of Textile Engineering

Offline Sumon Mazumder

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #4 on: October 27, 2011, 05:04:52 PM »
Thanks all who are involved here to share valuable information.


Thanks,

Sumon Mazumder
Lecturer
Dept. of TE
FSIT, DIU

Offline Subrata

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #5 on: October 27, 2011, 08:46:03 PM »
Thank you Sir for adding some other important information

Offline texsayem

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #6 on: October 28, 2011, 12:59:18 AM »
good job Baset...
Shahed Mohammad Kazi Shayemur Rahman
Lecturer,
Department of Textile Engineering
Daffodil International University

Offline fatima

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Re: Composition & Physical, Chemical, Thermal Properties of Cotton
« Reply #7 on: October 28, 2011, 02:14:30 PM »
very important information...................
Fatima Binta Satter Disha
Lecturer
Textile Engineering