Cotton is plentiful and economical to produce, it is relatively inexpensive and one of the world’s most important crops. Textiles, including lightweight voiles, laces, and heavy sailcloths and thick-piled velveteens, can be made with these fibres. They can be used for a large range of apparel, furnishings, and industrial applications.
What Is Cotton?
Cotton is a staple fiber, meaning there are varying lengths and types of fibers in it. Its plants, belonging to the genus Gossypium, are used to produce the cotton fibers used in this product.
The main component is cellulose, an insoluble organic compound essential to plant structure, and it is a fluffy and soft material. Its requires a lot of sunlight, a long period that does not involve frost, and a sufficient amount of rain.
Generally, It refers to the fibers that grow inside the boll of a cotton plant, thus the term cotton refers to the part of the plant that grows inside the boll. Soft, durable fabrics are made by spinning the fiber into yarn, which is then woven.
Scientific Classification
- Kingdom: Plantae
- Division: Magnoliophyta
- Class: Magnoliopsida
- Order: Malvales
- Family: Malvaceae
- Genus: Gossypium
Etymology
The word “cotton” has Arabic origins, derived from the Arabic word قطن (qutn or qutun). This was the usual word for cotton in medieval Arabic. Romance languages began to use the word in the middle of the 12th century, and English about a century later. The ancient Romans knew of its fabric as an import, but it was rare in the Romance-speaking lands until then until it was imported from the Arabic-speaking lands at lower prices in the late medieval era.
Cotton Genome
The genome of cotton is being sequenced in a public effort. Research began in 2007 by a group of public investigators. The researchers are trying to sequence the genome of a cultivated, tetraploid cotton plant. The “tetraploid” status refers to its two separate genomes, A and D. Due to the small size of this wild relative (G. raimondii, a Central American species) and its low repetition, the consortium agreed to sequence its D genome first.
Sequencing will be done on the A genome of G. arboreum. Genetically, it is roughly twice as large as G. raimondii. It is because of retrotransposons (GORGE) that the size difference is so great. After both diploid genomes are assembled, tetraploid genomes of cultivated species can be sequenced using them as models.
Considering a diploid genome as well as a euchromatic DNA sequence, the repetitive elements of AD and A genomes co-assemble into a single sequence, respectively. Unless AD sequences are compared to their diploid counterparts, we would never be able to unravel the mess of AD sequences.
In the public sector, efforts continue to generate high-quality, draft genome sequences using reads gathered from several sources. A total of 454 reads and Sanger reads were obtained from the BAC, fosmid, and plasmid sequences. In order to construct an initial draft of the D genome, these subsequent types of reads will be critical. A genome sequencing project completed by Monsanto and Illumina in 2010 covered Genome D of G. raimondii about 50x.
Raw reads will be donated to the public, according to the announcement. They used this publicity campaign to highlight their efforts to sequence the its genome. Having assembled the D genome from all of this raw material, it will undoubtedly help in assembling the AD genomes of the cotton varieties that are cultivated, although there is still much more to be done.
By 2014, cotton genomes had been assembled for at least one genus.
Where Did Cotton Originate?
In ancient times, it was produced in India, where it dates back to the 5th millennium B.C. The Arabic word “quton” is derived from the word “cotton.”
In the thirteenth century, an Indian inventor invented a cotton gin for separating fluff from plant seeds. Cotton production became easier and quicker after the cotton gin was invented, leading to it being used more widely as a textile.
With the inventions of new technologies such as the spinning jenny, spinning frame, and spinning mule during the Industrial Revolution, Britain grew to become one of the world’s largest cotton producers. This increased spinning rate was made possible by these machines.
In the United States and European Union, the mechanical cotton gin was invented by Eli Whitney and led to an increase in the production of the material. By eliminating the need for manual labour, this new tool reduced the amount of time needed for a bale of cotton to be produced from 600 hours to just 12. American cotton fibers, particularly those of the Southern states, started to get slightly longer and stronger around the same period.
The United States remains one of the world’s leading producers of cotton, just behind China and India, although there have been occasional drops, as during the Civil War.
Where Does Cotton Grow?
The United States, China, India, Uzbekistan, Pakistan, Brazil, and Turkey are all countries that grow cotton.
According to the University of Texas at Austin, Texas is the world’s largest producer of cotton, and the South Plains regions of the state are the largest contiguous cotton-growing areas.
Different Types of Cotton
There are four commercially grown species of cotton, all domesticated in antiquity:
- Gossypium hirsutum: This is native to the Central American region, Mexico, Caribbean, and southern Florida, accounting for 90% of world production.
- Gossypium barbadense: Tropical South American cotton, 8% of the world’s production, is known as extra-long-staple cotton.
- Gossypium arboreum: There are less than 2% of trees grown in India and Pakistan that produce this type.
- Gossypium herbaceum: Less than 2 percent comes from the Levant (South Africa, Arabian Peninsula).
Types of cotton based on fibre characteristics.
Pima cotton: Its fibers are extra soft and extra long, making it one of the finest types in the world. It originates from the American Southwest and South America. Mostly used in clothing, its fabric is a highly sought-after fabric because it resists fading, tearing, and wrinkleing.
Egyptian cotton: Pima cotton and Egyptian cotton have many similarities. In fact, they belong to the same scientific class as well: Gossypium barbadense. The plant grows in Egypt’s Nile River Valley, but it shares the same characteristics.
Upland cotton: Approximately 90% of the world’s cotton production comes from upland cotton, which has very short fibers. It is native to the Caribbean, Mexico, Central America and southern Florida, where it is grown.
Organic cotton: Cotton that is organic is grown without the use of chemicals and is obtained from plants that have not been genetically modified.
It is also possible to cultivate hybrid varieties. Despite the dominance of the New World cotton species in modern production, the two Old World cotton species were widely used up until the 1900s. Many cotton-growing locations have banned the growing of colored cotton varieties because they are afraid of contaminating the white cotton genetics. Its fiber naturally occurs in white, brown, pink, and green hues.
Cultivation of the Cotton Plant
All of the cotton species cultivated as agricultural crops are native to the subtropical regions of the world. They have been domesticated more than once independently. Usually produced as a shrubby annual in temperate climates, cotton can be found as a perennial treelike plant in tropical climates.
When grown under cultivation, it typically grows to a height of 1 to 2 meters (3 to 6.5 feet) rather than reaching heights of up to 6 meters (20 feet). White blossoms appear 80-100 days after planting, and they turn reddish after they change color.
After a few days, the fertilized blossoms fall off, and instead, they are replaced by triangular and green pods called bolls, which mature after a period of 55 to 80 days. During this time the seeds and hairs that attach to the seeds develop within the boll, which becomes much larger. Its fibres, or seed hair, can grow up to 6 cm (2.5 inches) in length, and are called lint in long-fibre varieties.
Seed hairs develop from a regrowth that occurs about 10 days after the first seed hairs. Linters, which are considerably shorter and less well connected to the seed, appear after a second growth. Bolls rupture into a white, fluffy ball bursting with seeds embedded in a mass of fibres. Each cell contains 7 to 10 seeds.
The seeds of the seed cotton, i.e., the part of the plant with the adhering hairs, make up two-thirds of its weight. Cellulose (a carbohydrate plant substance) makes up 87 to 90 percent of the fibres, followed by water (5 to 8 percent) and natural impurities (4 to 6 percent).
The best quality is obtained with high moisture levels due to rain or irrigation during the growing season, and a dry, warm period during picking. It can be grown between latitudes 30° N and 30° S, but yield and quality are significantly affected by climatic conditions.
To avoid wind or rain damage, cotton is collected as soon as the bolls open, but since the bolls do not all mature at the same time, mechanical harvesting is performed at the best time. In the process of handpicking, which takes several days, mature and opened bolls are selected in order to raise yield.
Cotton picked by hand is also much cleaner, whereas cotton picked by mechanical harvesters accumulates loose material, dust, and dirt, and cannot distinguish between good cotton and discolored cotton. Prior to mechanical picking, a chemical defoliant is typically applied to the plants to get them to shed their leaves, thus accelerating the ripening of the fruits more uniformly.
Morphology of Cotton
In comparison to other crops, it has a more complex structure. It develops from the surface layer of the cottonseed and is a single, elongated, multilayered dried cell.
This outermost layer is called the cuticle. There are pectins and proteinaceous materials present in this layer. Cell walls are derived from the original thin cell walls. It consists of fine filaments (small strands of cellulose) connected by a network of cellulose.
There are 4 layers of secondary thickening, the first being the winding layer, also known as S1. There is a structural difference between the secondary wall and both the primary and secondary walls. Fibrils are arranged in a woven pattern with an open net pattern, with an angle between 40 and 70 degrees from the fiber axis.
Cotton fiber is primarily made up of the S2 layer, or secondary wall, which is a chain of concentric layers of cellulose. In order to form the secondary wall, additional layers of cellulose are added after the fiber has reached its maximum diameter. At points along the length of the fiber, the angle of deposited fibrils reverses, resulting in 70- to 80-degree angles.
There is a hollow canal running the length of the fiber, known as the lumen. This cavity is filled with protoplasts during the growth period. A central pore space or void is naturally left behind in each fiber after maturing and opening up the boll. Apparently more resistant to certain reagents than secondary wall layers, it separates the secondary wall from the lumen. This layer is also known as S3.
Pests and Diseases
It is attacked by several hundred species of insects, including such harmful species as the boll weevil, pink bollworm, cotton leafworm, cotton flea hopper, cotton aphid, rapid plant bug, conchuela, southern green stinkbug, spider mites (red spiders), grasshoppers, thrips, and tarnished plant bugs. Planting at the right time of year or using other cultural practices can limit damage by insect pests, or you can breed varieties that are more resistant to insect damage.
Due to ecological concerns, chemical insecticides, first introduced in the early 1900s, must be used with caution and selectivity, but are a proven and efficient means of controlling insects. Organic cotton production, which relies on nonsynthetic insecticides, has increased in many countries around the world, in contrast to conventional cotton production that uses more insecticides.
In addition, it is ostensibly cheaper to use fewer pesticides when genetically modified cotton is used. By genetic engineering, it has also been possible to develop cotton that is resistant to glyphosate.
A number of insecticides, including chlorinated hydrocarbons and organophosphates, were eventually able to eradicate the cotton boll weevil (Anthonomus grandis), the most serious pest in the early 1900s.
The boll weevil is a pest that can be effectively controlled using a mixture of toxaphene and DDT (dichlorodiphenyltrichloroethane), which is illegal in most places but remains in place in some places.
Originally reported in India in 1842, the pink bollworm (Pectinophora gossypiella) has spread worldwide and accounts for up to 25 percent of global cotton crop losses in India, Egypt, China, and Brazil.
A few relatively small areas with sufficiently strict controls have been able to eradicate the insects through controls and quarantines. Cotton and many other wild and cultivated plants are host to the bollworm, known as Heliothis zea (corn earworm). Fortunately, insecticide applications can be helpful in controlling it.
A variety of pathogenic fungi, bacteria, and viruses can cause diseases in its plants, and nematodes (parasitic worms) and physiological disturbances can also cause disease. According to some estimates, some African and Brazilian countries have lost up to 50 percent.
It is common to treat seeds before planting, since young plants are particularly sensitive to disease. Breeding has developed varieties resistant to angular leaf spot, a bacterial disease.
Those disorders, which are confined to certain soil conditions, rainfall, and climate, can be moderately controlled through soil fumigation, such as fusarium wilt, verticillium wilt, and Texas root rot. It has been more effective, however, to breed resistant varieties.
Pests
- Boll weevil, Anthonomus grandis
- Cotton aphid, Aphis gossypii
- Cotton stainer, Dysdercus koenigii
- Cotton bollworm, Helicoverpa zea, and native budworm, Helicoverpa punctigera, are caterpillars that damage cotton crops.
- Some other Lepidoptera (butterfly and moth) larvae also feed on it – see list of Lepidoptera that feed on cotton plants.
- Green mirid (Creontiades dilutus), a sucking insect
- Spider mites, Tetranychus urticae, T. ludeni and T. lambi
- Thrips, Thrips tabaci and Frankliniella schultzei
Diseases
- Alternaria leaf spot, caused by Alternaria macrospora and Alternaria alternata
- Anthracnose boll rot, caused by Colletotrichum gossypii
- Black root rot, caused by the fungus Thielaviopsis basicola
- Blight caused by Xanthomonas campestris pv. malvacearum
- Fusarium boll rot caused by Fusarium spp.
- Phytophthora boll rot, caused by Phytophthora nicotianae var. parasitica
- Sclerotinia boll rot, caused by the fungus Sclerotinia sclerotiorum
- Stigmatomycosis, caused by the fungi Ashbya gossypii, Eremothecium coryli, (Nematospora coryli) and Aureobasidium pullulans
Growing and Harvesting
Plants grown as annual field crops in warm climates include the cotton plant, a woody perennial shrub. Since it can be grown in a variety of different environment and cultural conditions, cotton growers can choose from a variety of cotton varieties that are bred to be productive under different conditions. It is important to protect the plants from insects, diseases, and weeds once they are planted and start to grow.
Its fibers develop in three stages on the seed inside the boll after the plant flowers. As the fiber cells undergo elongation (from 0 to 27 days), their thin primary walls expand and surround a large vacuole, causing the cells to significantly enlarge. A secondary cellulose wall is deposited in the primary wall during the thickening phase (15 to 55 days).
By the time that fiber cells have reached their “maturation,” their secondary walls fill most of the fiber cell space, leaving only a small central cavity (the lumen) containing cytoplasm and vacuoles. The fiber cells collapse as the boll opens, rapidly desiccating and dying. Convolutions denote the twisting of tubular cells as they fall, assuming a flat, ribbonlike shape.
To prevent tripping hazards during mechanical harvest, plants are defoliated before harvesting. Around 85% of the total American harvest is harvested by machines, while 15% is stripped by machines, primarily in Texas and Oklahoma. The cotton is harvested from open berries, leaving unopened and empty berries on the plant.
A rotating spindle pulls fiber out of the boll through revolving motion. Bolls open and unopened are stripped from the plant using machine strippers. “Seed cotton” refers to the fiber that has been harvested from the plant along with cottonseeds. The harvested seed cotton is transported to the gin.
How Is Cotton Processed?
From the planting of cotton seeds to harvesting to the ginning, cotton production is a fascinating process.
- In the past, it was picked and separated by hand, but nowadays most cotton is harvested by cotton pickers (which pick the entire plant) or by cotton strippers, which remove the bolls from the plant.
- It is baled in the field after it is picked and stored there for some time before it is sent to be ginned.
- Ginners clean and fluff cotton bales to remove dirt, seeds, and lint from the material.
- In the cotton gins, the cotton is combed and separated from the seeds before being compressed and stored. The raw cotton is then shipped off to textile mills to be used in the manufacturing process.
- A carding machine is used to separate the fibers into long ropes, which are ready for spinning and weaving. After the cotton is cleaned and fluffed, it goes through a carding machine which further cleans and fluffs the material.
Cotton Fiber and Cottonseed
Cotton balls are the fruits of cotton plants. Cotton seeds are enclosed in cellulose fibers, forming the cotton boll. Bolls split open when they are ripe, revealing the fibers within. As a result of the cellulose’s arrangement, the fibers have a high degree of durability, strength, and absorbency.
Biological fibers are composed of twenty to thirty layers of cellulose coiled around one another in a series of springs. In the process of opening a boll, the fibers dry and become interlocked together and flat in twisted shapes. The interlocking pattern is ideal for spinning into fine threads and yarns.
There are many textile products made from its fiber. In addition, terrycloth is used to make highly absorbent bath towels and bathrobes; denim, or blue jeans; chambray—they’re popular for blue shirts; and corduroy; seersucker, and cotton twill.
Almost all t-shirts, socks, and underwear are made from cotton. The same can be said for bedding. Crochet and knitting yarns are also made from cotton. Some fabrics are complete cotton blends, whereas others use synthetic fibers such as polyester or rayon.
Textiles are not the only products made from cotton. Cotton is also used in fishnets, coffee filters, tents, and bookbinding. Like the modern United States dollar bill and other federal stationery, China’s first paper was made of cotton fiber.
Cotton oil is extracted from the seeds that remain after the fibers are ginned (the seeds and fibers are separated). Humans can consume cottonseed oil like any other vegetable oil once it has been refined. Once the oil has been refined, the meal is usually fed to livestock.
Ginning
In the purest sense, ginning is the removal of cotton fibers from seeds — a process that was invented by Eli Whitney in 1794. Nowadays, cotton gins perform a range of functions. Almost all cotton harvests are turned into marketable products (fiber and seed) after the cotton is dried, cleaned (removing plant parts and field trash) separated from the seed and fiber, and then placed in an acceptable package while maintaining its quality.
“Saw gins” separate seeds and fiber in American upland cotton by pulling seed cotton between ribs with saw teeth. Bales can be produced at speeds of up to 12 (480-lb) bales per hour using saw gin stands. Cotton-producing areas throughout the United States are home to about 835 saw gins. Unlike saw ginning, roller ginning is only done in areas (West Texas, New Mexico, Arizona, and California) that produce Pima cotton. Roller ginning is a quieter, gentler process than saw ginning.
Cotton fiber and cottonseed are two products derived from ginning that have a cash value. Ginning releases the fiber into bales, allowing it to be compressed into yarn. Samples of fiber taken from both sides of each bale are sent to U.S. Department of Agriculture for classification, at which point the fiber is called “raw cotton.” When the cottonseeds are removed during ginning, they are sent to cotton oil mills.
The seeds still contain short fibers caused by ginning that were not removed. Oil mills use delinting machines in the same way that saw gins do to remove linters from seeds. Mill-run linters are made by seedlings that are run through a delinting machine a single time.
The seed is generally run through the mill twice, so “first-cut” and “second-cut” linters are produced. In many nonwoven products, first-cut linters are used, because they have longer, more flexible fibers. Linters are used as cellulose sources in the chemical industry and in the production of high grade paper from their shorter fibers. Linters are removed before being converted into food, feed, fertilizer, and mulch. Cottonseed is all these things after it is stripped of its linters.
Motes, which are small seedlings with fiber attached, are also by-products of the ginning process. At a different stage in the process, these are removed. An automatic linting machine can remove the fiber from the motes. In addition to being used in nonwoven products, this fiber is called “gin mote fiber.”
What Are the Characteristics of Cotton?
There are a number of distinct qualities about cotton that make it such a popular fiber in the textile industry.
- Softness: Typically cotton fabrics retain that soft touch because the cotton plant is soft and fluffy.
- Durability: Cotton plants have tough cellular structures, which produces a fabric that is hardy and resistant to wear.
- Absorbency: The space between cotton fibers makes cotton fabric very absorbent.
- Holds dye well: Because of cotton’s absorbent nature, it can easily be dyed and dyed in endless combinations.
- Breathability: Fabrics made from cotton have a fiber structure that makes them more breathable than synthetic fabrics.
- No static cling: Cotton is electrically inert, which means static electricity can’t occur.
Physical Properties of Cotton
In nonwovens, micronaire, length, and strength are the three main properties of cotton. Aspects of visual appearance may also be factored into the design of nylon.
Micronaire
Micronaire is a way of measuring the fineness of fibers by airflow. The test is performed by compressing a specimen to a specific volume in a chamber after it is weighed. In order to measure the resistance to airflow, the specimen is forced to run through air. Micronaire and maturity of the fiber (because they are highly correlated within cotton varieties) determine the resistance of the fiber (expressed in micrograms per inch). In order to determine the exact linear density of the fibers, another measurement needs to be performed to determine the fiber maturity. Upland cotton ordinarily ranges from about 0.7 to 2.3 denier. Upland cotton ranges in denier from 0.7 to 2.3, because denier is equal to micronaire divided by 2.82.
Fiber Length
A sample of cotton fiber shows a wide range of fiber length because it differs genetically from sample to sample. Fiber length in HVI is the average length of the longer half of the fibers (the upper half-mean length) measured in 100ths of an inch. Upland cotton fibers are generally 1.25 inches or longer, 1.6 inches or longer for Pima cotton, and less than 0.5 inches for linters (rinses and noils that are left over after combing).
Fiber Strength
A bunch of fibers is clamped between two sets of jaws, with 1/8 inch between the jaws, and the force required to break them is measured with the HVI system. A bunch of fibers is clamped between two sets of jaws, with 1/8 inch between the jaws, and the force required to break them is measured with the HVI system. HVI measures the force required to break a bunch of fibers clamped between two sets of jaws. The force is expressed in grams per tex or grams per denier. “Tex” is a unit of weight equal to 1,000 meters of fiber weighing 100 grams. The strength is the amount of force in grams it takes to break a bundle of fibers, which is one tex unit in size.
Neps
“Neps” are small knots of tangled fibers. They are usually created by biological or mechanical processes. NEPS cause white specks to appear on fabrics, which can detract from their appearance. The number of neps measured per gram of cotton and the diameter of the nep are reported by the Zellweger Uster Advanced Fiber Information System (AFIS) nep tester. Using the right equipment and setting will minimize nep formation during the processing process.
6 Common Uses for Cotton
Many industries utilize cotton, including textiles, clothing, and furniture.
- Woven fabrics: There are many fabrics made from cotton, including canvas, denim, damask, flannel, and more.
- Clothing: Due to its mass production, softness, durability, and absorbency, it has become a fixture in the textile industry. Tee shirts, blue jeans, dresses, sweatshirts, and so much more are commonly crafted from this material.
- Bedsheets and towels: It is an ideal fabric for toweling and bed linens that need to absorb moisture since cotton is so soft and absorbent.
- Underwear: It makes undergarments that are comfortable and durable for the same reason.
- Home decor: Upholstery, curtains, rugs, and pillows are also made from this fabric.
- Cottonseed oil: It is manufactured from seeds, which can be used in salad dressings and margarine. Cottonseed is a byproduct of cotton production. Besides being an ingredient in makeup, soap, and candles, it can be used in other products.
Source: Sustainable Cotton Cluster
Source: Masterclass, Britannica, Cottoninc, Wikipedia, New World Encyclopedia
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