Cellulose is a fibrous material of plant origin and the basis of all natural and man-made cellulosic fibres. The natural cellulosic fibres include cotton, flax, hemp, jute, and ramie. Cellulose is a polymeric sugar polysaccharide) made up of repeating 1,4-8-an hydro glucose units connected to each other by 8-ether linkages. Strong intermolecular forces between chains, coupled with the high linearity of the cellulose molecule, account for the crystalline nature of cellulosic fibres. Previous Topic » Natural Fibres - fibres from the nature
Next Topic » Properties of Vegetable/Plant/Cellulosic fibres
 The natural fibers are vegetable, animal, or mineral in origin. Vegetable
fibers, as the name implies, are derived from plants. The principal chemical component in plants is cellulose, and therefore they are also referred to as cellulosic
fibers. The fibers are usually bound by a natural phenolic polymer, lignin, which
also is frequently present in the cell wall of the fiber; thus vegetable fibers are
also often referred to as lignocellulosic fibers, except for cotton, which does not
contain lignin. Cellulose is a fibrous material of plant Origin and the basis of all natural and man-made cellulosic fibers. The natural cellulosic fibers include cotton, flax, hemp, jute, and ramie. The major man-made cellulosic fiber is rayon, a fiber produced by regeneration of dissolved forms of cellulose. Cellulose is a polymeric sugar (polysaccharide) made up of repeating 1,4-8-an hydroglucose units connected to each other by 8-ether linkages. The long 1inear chains of cellulose permit the hydroxyl functional groups on each anhydro glucose unit to interact with hydroxyl groups on adjacent chains through hydrogen bonding and van der Waal s forces. These strong intermolecular forces between chains, coupled with the high linearity of the cellulose molecule, account for the crystalline nature of cellulosic fibers.
Vegetable fibers are classified according to their source in plants as follows:
(1) the bast or stem fibers, which form the fibrous bundles in the inner bark
(phloem or bast) of the plant stems, are often referred to as soft fibers for textile
use; (2) the leaf fibers, which run lengthwise through the leaves of monocotyledonous plants, are also referred to as hard fibers; and (3) the seed-hair fibers,
the source of cotton, which is the most important vegetable fiber. There are >250,000 species of higher plants;
however, only a very limited number of species have been exploited for commercial uses (<0.1%). The fibers in bast and leaf fiber plants are integral with the plant
structure, providing strength and support. In bast fiber plants, the fibers are
next to the outer bark in the bast or phloem and serve to strengthen the stems
of these reed-like plants. The fibers are in strands running the length of the stem
or between joints. To separate the strands, the natural gum binding
them must be removed. This operation is called retting (controlled rotting). For
most uses, particularly for textiles, this long composite-type strand fiber is used
directly; however, when such fiber strands are pulped by chemical means the
strand is broken down into much shorter and finer fibers, the ultimate fibers. The long leaf-fibers contribute strength to the leaves of certain nonwoody,
monocotyledonous plants. They extend longitudinally the full length of the leaf
and are buried in tissues of a parenchymatous nature. The fibers found nearest
the leaf surface are the strongest. The fibers are separated from the pulp tissue
by scraping because there is little bonding between fiber and pulp; this operation
is called decortication. Leaf fiber strands are also multicelled in structure.
Ancient humans used cordage in fishing, trapping, and transport, and in
fabrics for clothing. Rope and cord making started in Paleolithic times, as
seen in cave drawings. Rope, cords, and fabrics were made from reeds and grasses in ancient Egypt (400 BC). Ropes, boats, sails, and mats were made from palm
leaf fibers and papyrus stalks and writing surfaces, known as papyrus, from the
pith section. Jute, fiax, ramie, sedges, rushes, and reeds have long been used
for fabrics and baskets. Jute was cultivated in India in ancient times and used
for spinning and weaving. The first true paper is believed to have been made in
southeastern China in the second century AD from old rags (bast fibers) of hemp
and ramie and later from the bast fiber of the mulberry tree. World markets for vegetable fibers have been steadily declining in recent
years, mainly as a result of substitution with synthetic materials. Jute has traditionally been one of the principal bast fibers (tonnage basis) sold on the world
market; however, the precipitous decline in jute exports by India indicate
the decreasing market demand for this fiber that has been vitally important to
the economies of India (West Bengal), Bangladesh, and Pakistan.
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Cotton is the most commonly used natural cellulosic fiber. Cotton fibers grow from the seeds in the boll (seedpod). Each boll contains seven or eight seeds, and each seed may have up to 20,000 fibers growing from it. |
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Coir is from the fibrous mass between the outer shell and husk of coconuts. It is a stiff fiber. It is usually used to make highly durable indoor and outdoor mats, rugs, and tiles. |
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Kapok fiber is from the seed of the Java or Indian kapok tree. The fiber is soft, lightweight, and hollow. It breaks down easily and it is difficult to spin into yarns. It is used as fiberfill and as the stuffing for pillows. It used to be used as a stuffing for lifejackets and the mattresses on cruise ships because it is very buoyant.
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Milkweed has properties similar to those of kapok.
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Flax is one of the oldest textile fibers, but its use has declined since the invention of power spinning for cotton. Flax fabric is linen, although the word linen is now often used to refer to table, bed, and bath fabrics made from other materials |
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Ramie fibers are 4 to 6 inches long. The fibers are whiter and softer than flax. Ramie does not retain dyes well unless it is dry-cleaned. Ramie is strong for a natural fiber, but it lacks resiliency, elasticity, and elongation potential. It is resistant to mildew, insects, and shrinkage. It is used for apparel, window treatments, ropes, paper, and table and bed linens |
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Hemp is similar to flax. The fibers range in length from 3 to 15 feet. Hemp production is illegal in the U.S. Hemp has a low environmental impact; it does not require pesticides. It produces 250% more fiber than cotton and 600% more fiber than flax on the same amount of land. Hemp plants can be used to extract zinc and mercury pollutants from soil. Hemp is used for ropes, apparel, and paper. Potheads are willing to pay inflated prices for hemp apparel because it is related to the marijuana plant |
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Jute is one of the cheapest textile fibers, and one of the weakest cellulosic fibers. Jute has poor elasticity, elongation, sunlight resistance, mildew resistance, and colorfastness. It is used to produce sugar and coffee bagging, carpet backing, rope, and wall coverings. Burlap is made from jute. |
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Piña fibers are from the leaves of the pineapple plant. It is used to make lightweight, sheer, stiff fabrics for apparel, bags, and table linens. It is also used to make mats. |
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Abaca is from a member of the banana tree family. The fibers are coarse and very long (up to 15 feet). It is a strong, durable, and flexible fiber used for ropes, floor mats, table linens, apparel, and wicker furniture. |
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Properties |
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Ramie
Ramie is one of the oldest fibre crops, having been used for at least six thousand years. It is also known as china grass.
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- Ramie requires chemical processing to de-gum the fibre.
- It is fine absorbent, quick drying fibre, is slightly stiff and possesses high natural lustre.
- Its plant height is 2.5m and its strength is eight times more than cotton
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Hemp
Depending on the processing used to remove the fiber from the stem, the hemp naturally may be creamy white, brown, gray, black or green.
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- It is yellowish brown fibre
- Hemp fibers can be 3 to 15 feet long, running the length of the plant
- Characteristics of hemp fibre are its superior strength and durability, resistance to ultraviolet light and mold, comfort and good absorbancy
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Jute
Jute is one of the cheapest natural fibres and is second only to cotton in amount produced and variety of uses. Jute fibres are composed primarily of the plant materials cellulose and lignin.
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- Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads.
- It is thus a ligno -cellulosic fibre that is partially a textile fibre and partially wood.
- The plant grows up to a height of 2.5m and its fibre length is about 2m.
- It is generally used in geo textiles.
- It has a good resistance to micro organisms and insects.
- It has low wet strength, low elongation and inexpensive to produce
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Coir
Fibre mechanically extracted from dry mature coconut husk after soaking.
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- It is long, hard and strong fibre but with lower softness, lower water absorption capacity, and shorter life than long retted fibre.
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Kapok
Kapok fiber is a silky cotton-like substance that surrounds the seeds in the pods of the ceiba tree.
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- It can support as much as 30 times its own weight in water and loses only 10 percent of buoyancy over a 30-day period.
- It is eight times lighter than cotton
- It is extremely used as a thermal-insulator.
- It is also lightweight, non-allergic, non-toxic, resistant to rot and odorless.
- Since it is inelastic and too fragile, it can't be spun.
- It has outstanding characteristics of lightness, impermeability, thermal-isolation and eco- naturality.
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All fibres which come from natural sources (animals, plants, etc.) and do not require fibre formation or reformation are classed as natural fibres. The natural fibres are vegetable, animal, or mineral in origin. Some of the natural fibres like vegetable fibres are obtained from the various parts of the plants. They are provided by nature in ready-made form. It include the protein fibres such as wool and silk, the cellulose fibres such as cotton and linen, and the mineral fibre asbestos. Chemically, cotton is the purest vegetable fibre, containing >90% cellulose with little or no lignin. |