![Principlesofdyei00frap 0075](https://upload.wikimedia.org/wikipedia/commons/b/b9/Principlesofdyei00frap_0075.jpg)
Dead cotton () is a term that refers to unripe
cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...
fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
s that do not absorb
dye
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...
. Dead cotton is
immature cotton or underdeveloped cotton that has poor dye affinity and appears as white specks on a
dyed
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular ch ...
fabric
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the ...
.
Daniel Koechlin
The Koechlin family is an Alsatian family which acquired its wealth in the textile industry and became leading industrialists and politicians of the region.
Early family history
The first traces of the family can be found in 1440, when Johann Koe ...
(1785–1871), who was a manufacturer and a chemist in
Mulhouse
Mulhouse (; Alsatian language, Alsatian: or , ; ; meaning ''Mill (grinding), mill house'') is a city of the Haut-Rhin Departments of France, department, in the Grand Est Regions of France, region, eastern France, close to the France–Switzerl ...
, established the fact in 1848 that it is dead cotton fibers that resist dye. Other chemists such as
Walter Crum
Walter Crum FRS (1796–1867) was a Scottish chemist and businessman. He became a Fellow of the Royal Society in 1844.
Life
He was born in Glasgow, the second son of Alexander Crum of Thornliebank, a merchant there, and of Jane, the eldest da ...
,
Albin Haller
Albin Haller (7 March 1849, Fellering – 1 May 1925) was a French chemist.W. J. Pope (1925) ''Nature'', Vol.115(2900), p.843 "Prof. Albin Haller, For. Mem. R.S" (obituary)
Haller founded the École Nationale Supérieure des Industries Chim ...
, and Herzog explored and contributed to the subject further. Crum discovered that dead fibers have very thin cell walls.
Grading
![Baumwollfaser Querschnitt](https://upload.wikimedia.org/wikipedia/commons/2/2d/Baumwollfaser_Querschnitt.png)
Grading is the process of
classifying cotton fibers based on certain parameters like the
length of the staple, the strength of the fibers, and how even they are.
There are ripe, unripe, and half-ripe cotton fibers in every lot of cotton, because the seed has fibers that grow at different maturity rates. Matured fibers are ones that have completed their growth process and have developed in all aspects. Cotton fiber has a cell wall and a
lumen, and the cell wall thickens as the fiber matures. The cell wall makes up 50–80% of the cross-section of a mature cotton fiber, 30–45% of an immature cotton fiber, and less than 25% of a dead cotton fiber.
Dead or immature fibers show no tubular structure like matured fibers, instead they look like broad, solid, ribbon-like fibers which are almost transparent, with irregular twists.
Microscopic view
When cotton fibers are analyzed and assessed through a microscope, dead fibers appear differently. Dead cotton fibers have thin cell walls. In contrast, mature fibers have more cellulose and a greater degree of cell wall thickening.
Microscopic views of dead fibers exhibit extremely thin cell walls; the fibers appear as flattened and slightly twisted tapes, with collapsed lumen.
Significance
Dead cotton is observed as a serious defect in dyed fabrics. The problem is that it is apparent after it has been dyed.
The dead fibers are difficult to spin; they lack twist and are brittle and weak.
Dead fibers cause a poor surface appearance of the textile product, with increased nep grade and uneven dyeing. Any remedial action of dead cotton is really significant.
Remedies
There are a few treatments that can help mitigate the effect of dead cotton in finished products.
* In yarn
spinning
Spin or spinning most often refers to:
* Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning
* Spin, the rotation of an object around a central axis
* Spin (propaganda), an intentionally b ...
, a process called
combing is used to remove short and undesirable fibers which is referred to as "
noil". The combing helps in reducing the immature fibers.
*
Mercerization
Mercerisation is a textile finishing treatment for cellulose fabric and yarn, mainly cotton and flax, which improves dye uptake and tear strength, reduces fabric shrinkage, and imparts a silk-like luster.
Development
The process was devis ...
is a pretreatment that alters the fiber properties and avoids dead fibers, which helps in level dyeing.
* There are certain
enzymes
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
, such as
cellulase
Cellulase (EC 3.2.1.4; systematic name 4-β-D-glucan 4-glucanohydrolase) is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharide ...
, which can cut down on the protruding fibers and consequently reduce the dead fibers. The treatment is also called "depilling" or "biopolishing".
* Chitosan after-treatment helps in increasing the exhaustion of direct dyes and reducing the white specks caused by dead cotton. It produces superior results when redyed with a modest proportion of dye following chitosan treatment.
* There are certain
direct dyes which have an ability to cover/dye dead cotton.
See also
*
Dead wool is the wool which is pulled from a dead sheep.
*
Yarn realisation
References
{{Spinning
Cotton
Spinning