Cellulosic Fibres

CELLULOSIC FIBRES

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FIBRE:-Fiber or fibre is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread. Natural fibers-

Vegetable fibre Animal fibre Mineral fibre

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Man-made fibers

May come from natural synthetic chemicals

CELLULOSIC FIBRES

NATURAL CELLULOSIC • • • • • • • • •

COTTON LINEN JUTE HEMP SISAL KAPOK RAMIE COIR PINA

MANMADE CELLULOSIC • • • •

RAYON ACETATE TRI ACETATE Cupra Ammonium

COTTON

Properties of cotton fibers Property

Evaluation

Shape

Fairly uniform in width, 12-20 microns; length varies from ½ to 2½ inches; typical length is ⅞ to 1¼ inches.

Luster

low

Tenacity (strength) Dry Wet

3.0-5.0 g/d 3.3-6.0 g/d

Resiliency

low

Density

1.54/1.56 g/ccm

Moisture absorption raw:conditioned saturation mercerized: conditioned saturation

8.5% 15-25% 8.5-10.3% 15-27%+

Dimensional stability

good

Resistance to acids alkali organic solvents sunlight microorganisms insects

damage, weaken fibers resistant; no harmful effects high resistance to most Prolonged exposure weakens fibers. Mildew and rot-producing bacteria damage fibers. Silverfish damage fibers.

Thermal reactions to heat to flame

Decomposes after prolonged exposure to temperatures of 150˚C or over. Burns readily.

TYPES OF COTTON

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The following species are grown commercially: Gossypium arboreum L. – Tree cotton, native to India and Pakistan.

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Gossypium barbadense L. – known as American Pima, Creole, Egyptian, or Sea island cotton, native to tropical South America.

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Gossypium herbaceum L. – Levant cotton, native to southern Africa and Arabian Peninsula.

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Gossypium hirsutum L. – Upland cotton, native to Central America, Mexico, the Caribbean and southern Florida - most commonly grown species in the world.

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Gossypium peruvianium

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Gossypium purpurascade

COTTON LONGITUDINALSECTION

•Also cotton has a Bean-shaped cross section

Yarn Manufacturing Processes Plucking:2. Manual 3. Mechanical Picking:- open tufts are collected and rolled into a batt. Then batt is removed from the cylindrical screens of the picker in an even flat sheet and rolled into a lap

Ginning Harvested raw cotton Contains seeds, leaf fragments etc. Cottonseeds weigh 2/3rds of raw cotton when picked. These are removed by a cotton gin. Cotton gin has saw-toothed bands that pull the fiber from the seeds. Then cotton fiber is compressed into rectangular bales, covered with jute or polypropylene bagging and bound with iron bands.

Opening and blending 

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The sequential production process begins by converting the compacted layers of baled cotton into small, light, fluffy tufts that facilitate removal of foreign matter. This initial process is called “opening”. Since bales are of different density, they are cut 24 hrs before processing in order to allow them to “bloom”.

Scutching 

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It refers to the blow room operations. The resultant is a cotton lap

Carding The card successively works on small tufts of fibres separating or opening them ,removing a high percentage of trash and other foreign matters collecting the fibre in a rope-like form called “sliver” and delivering it for further processing. The fibres are made parallel to each other and their direction is oriented.

Combing

•Provides more extensive cleaning than carding •Removes short fibres neps and trash so that the resulting sliver is clean and lustrous.

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4. 5.

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Drawing and roving –first or initial twist to the yarn is given. Its diameter is 2mm -3mm Spinning-production of yarn by twisting the yarn. Its of 2 types Open-end spinning Close-end spinning Doubling- each yarn has two single yarns, to make it stronger Sizing, Gassing- done to give uniformity to the yarn

VARIOUS FINISHES OF COTTON 

Mercerization- adds strength, improves lustre, absorbency, dyeability

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Sanforization-ensures less than 1 % shrinkage

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Moireing- for variable luster and variable pattern

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Glazing-gloss, smoothness and embossed effects

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Stiffening- smoothen, stiffens and strengthens

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Wrinkle resistant permanent press- improves shaperetension and imparts dip-dry characteristic Schreinerizing-adds luster

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Stain repelling-for easy care

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Napping-for softness, warmth and increased absorbency

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Singeing-for smoothness

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Weighting-for bulk

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Insulating-for warmth

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Embossing-for decoration

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Mildew resistant

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Fire-retardant

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Moth-resistant

ADVANTAGES  2. 3. 4.

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 9. 10. 11.

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It can be processed into a wide selection of fabricsSheer fabrics- cambric,batist chiffon,lawn,organdy and voile. Medium weight cottonsbroadcloth,drill,flannel,poplin,terry cloth and long cloth. Heavy weight cottons-brocade,corduroy,denim,pique and velveteen Can be mercerized to improve luster, absorbency,dyeability and strength. Textured effects are easily achieved byChanging yarn structure-high twist yarns,nub yarns, bouclé yarns, crimped yarn Changing fabric construction- crepes,serersuckers Application of special finishes- embossing and napping Can be easily dyed or printed with almost all classes of dyes. Good absorbent, Does not build up static electricity, Good conductor of heat

Limitations 

Untreated cotton wrinkles easily

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Susceptible to mildew if left damp

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Flammable

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Takes a long time to dry

SISAL •The sisal plant has a 7-10 year life-span and typically produces 200-250 commercially usable leaves. •Each leaf contains an average of around 1000 fibers. • It is extracted by a process known as decortication.

USES Sisal is used in three grades: 3. The lower grade fiber is processed by the paper industry because of its high content of cellulose and hemicelluloses. 5. The medium grade fiber is used in the cordage industry for making: ropes, baler and binders twine 7. The higher-grade fiber after treatment is converted into yarns

LINEN Linen or flax fibres are extracted from the stem or bast of flax plant Fibres held together by gummy substance called as Pectin Flax fibre basically composed of Cellulose

QUALITY AND GRADES  Countries cultivating flax plant are Belgium Scot France Russia Germany

Countrai flax produces the finest and strongest yarn from Belgium

METHODS OF SEPARATION OF LINEN • • 4.

CULTIVATION: April or May HARVESTING: By the end of August PREPARATION OF FIBRES: 

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Rippling/Threshing – seeds and leaves removal from stem. Retting – Most important process where stems are left under moistened condition to decompose and separation of fibers.

Types of retting : 1. 2. 3. 4. 5.

Dew retting Pool or Dam retting Stream retting Vat retting Chemical retting

4. Manufacturing process: Breaking Scutching Hackling (Coming) Spinning.

CONSTRUCTION OF LINEN FABRICS 

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Inelastic so usually break during weaving process Very moist atmosphere is required. Generally not knitted because of a) Inherent stiffness

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b)Resistance to being formed

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SO, usually blended with cotton or other man made fibres

END PRODUCTS OF LINEN FARICS 

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Apparel fabrics – shirt, skirt,jackets etc. Accessories fabric- pockets,bags etc. House hold textiles- bed n table clothing etc. Industrial textiles- tarpaulins, ropes etc

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It is very durable, two or three times stronger then cotton. High absobency,smoothness so comfortable to wear. Good resistance to alkalies and bleaches. Easily dyed and printed. Withstand high ironing temperature.

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Linen wrinkles easily. Lacks flex abrasion n hence shows wear on crease lines n seams Fabrics take long time to dry. It is imflammable. Susceptible to mildew if left damp. It has poor press-crease retention.

Jute SOURCE •Jute is one of the strongest natural fibres •The jute fibre comes from the stem and ribbon (outer skin) of the jute plant. •The production is concentrated in Bangladesh, India, China, and Thailand. It is the second most important vegetable fibre after cotton, in terms of usage, global consumption, production, and availability. •It is the second most important vegetable fibre after cotton, in terms of usage, global consumption, production, and availability

MANUFACTURING PROCESS The fibres are first extracted by retting.  The retting process consists of bundling jute stems together and immersing them in low, running water. 

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There are two types of retting: stem and ribbon. After the retting process, stripping begins. In the stripping process, nonfibrous matter is scraped off, then the workers dig in and grab the fibres from within the jute stem.

PROPERTIES 

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Jute fibre is 100% bio-degradable and recyclable and thus environmentally friendly. It is a natural fibre with golden and silky shine and hence called The Golden Fibre. It is the cheapest vegetable fibre procured from the bast or skin of the plant's stem. It has high tensile strength, low extensibility, and ensures better breathability of fabrics.

ADVANTAGES 

good insulating and antistatic properties

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low thermal conductivity

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moderate moisture regain.

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acoustic insulating properties

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no skin irritations.

DISADVANTAGES 

poor drapability

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Brittleness

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fibre shedding

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yellowing in sunlight

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Jute has a decreased strength when wet

USES •It is used as substitute for hemp

JUTE MATS

•As binding thread for carpet and rugs, rug cushions, filler with other fibers. • As a linoleum base •Made into cheap coarse fabrics •Heavy bagging.

COIR

SOURCE • Coir fibers are found between the husk and the outer shell of a coconut. • The individual fiber cells are narrow and hollow, with thick walls made of cellulose. The coir is of two types: 7. Brown coir 8. White coir

MANUFACTURING PROCESS BROWN COIR •Brown coir is harvested from fully ripened coconuts •The fibrous layer of the fruit is then separated from the hard shell (manually) by driving the fruit down onto a spike to split it (De-husking •The fibrous husks are soaked in pits or in nets in a slow moving body of water to swell and soften the fibres •. The long bristle fibres are separated from the shorter mattress fibres underneath the skin of the nut, a process known as wet-milling •The mattress fibres are sifted to remove dirt and other rubbish, dried in the sun and packed into bales

WHITE COIR 

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White coir fibers are harvested from the coconuts before they are ripe The immature husks are suspended in a river or water-filled pit for up to ten months. During this time micro-organisms break down the plant tissues surrounding the fibres to loosen them - a process known as retting Segments of the husk are then beaten by hand to separate out the long fibres which are subsequently dried and cleaned Cleaned fibre is ready for spinning into yarn using a simple onehanded system or a spinning wheel.

RETTING

PROPERTIES 

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Mature brown coir fibers contain more lignin and less cellulose than fibers such as flax and cotton and so are stronger but less flexible They are made up of small threads, each about 1 mm long and 10 to 20 micrometres in diameter The fibers are white or light brown in color and are smoother and finer, but also weaker

USES 

Brown coir is used in floor mats and doormats, brushes, mattresses, floor tiles and sacking.

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Used to make twine

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Used to fill mattresses

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The major use of white coir is in rope manufacture

HEMP The fiber is one of the most valuable parts of the hemp plant. It is commonly called "bast", meaning it grows as a stalk from the ground

PROPERTIES •The inner two fibers of hemp are more woody, and are more often used in non-woven items and other industrial applications •Hemp fibers can be 3 to 15 feet long, running the length of the plant. •the hemp naturally may be creamy white, brown, gray, black or green

USES

•the manufacture of cordage of varying tensile strength •clothing •nutritional products •hemp fibers are increasingly used to strengthen cement

RAMIE:Ramie (Boehmeria nivea) is a flowering plant in the nettle family native to eastern asia. The true ramie or china grass also called chinese plant or white ramie is the chinese cultivated plant.A second type is known as green ramie or rhea and is believed to originate from malay peninsula.it is suitable in tropical climate….. Ramie is one of the oldest fibre crops, having been used for at least six thousand years, and is principally used for fabric production. It is a bast fibre, and the part used is the bark of the vegetative stalks. Ramie is normally harvested two to three times a year but under good growing conditions can be harvested up to six times per year.Unlike other bast crops, ramie requires chemical processing to de-gum the fibre.

Properties Ramie is one of the strongest natural fibers. It exhibits even greater strength when wet. Ramie fiber is known especially for its ability to hold shape, reduce wrinkling, and introduce a silky lustre to the fabric appearance. It is not as durable as other fibers, and so is usually used as a blend with other fibers such as cotton or wool. It is similar to flax in absorbency, density and microscopic appearance. However it will not dye as well as cotton. Because of its high molecular crystallinity, ramie is stiff and brittle and will break if folded repeatedly in the same place; it lacks resiliency and is low in elasticity and elongation potential.

Uses Despite its strength, ramie has had limited acceptance for textile use. The fiber's extraction and cleaning are expensive, chiefly because of the several steps— involving scraping, pounding, heating, washing, or exposure to chemicals. Some or all are needed to separate the raw fiber from the adhesive gums or resins in which it is ensheathed. Spinning the fiber is made difficult by its brittle quality and low elasticity; and weaving is complicated by the hairy surface of the yarn, resulting from lack of cohesion between the fibers. The greater utilization of ramie depends upon the development of improved processing methods.

•Kapok (Ceiba pentandra) is a tropical tree of the order Malvales and the family Malvaceae (previously separated in the family Bombacaceae), native to Mexico, Central America and the Caribbean, northern South America, and (as the variety C. pentandra var. guineensis) to tropical west Africa. The word is also used for the fibre obtained from its seed pods. The tree is also known as the Java cotton, Java kapok, or ceiba. It is a sacred symbol in Maya mythology.

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Uses

The fibre is light, very buoyant, resilient, highly flammable and resistant to water. The process of harvesting and separating the fibre is labour-intensive and manual. It cannot be spun but is used as an alternative to down as filling in mattresses, pillows, upholstery, teddy bears, zafus and for insulation. It was previously much used in life jackets and similar devices. The fibre has been largely replaced by man-made materials. The seeds produce an oil used locally in soap and that can be used as fertilizer.

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Piña

Piña is a fiber made from the leaves of a pineapple and is commonly used in the Philippines. It is sometimes combined with silk or polyester to create a textile fabric. The end fabric is lightweight, easy to care for and has an elegant appearance similar to linen

Major Fiber Properties 

Piña comes from the leaves of the pineapple plant. "Each strand of the hand scrapped Piña fiber is knotted one by one to form a continuous filament for hand weaving into the Piña cloth". The piña fiber is softer, and has a high luster, and is usually white or ivory in color.

Production Methods  

Scraping a pineapple leaf to reveal the fibers. Since piña is from a leaf, the leaf has to first be cut from the plant. Then the fiber is pulled or split away from the leaf. Most leaf fibers are long and somewhat stiff.

Uses 

A major use for piña fabric is in the creation of the Barong Tagalog and other formal wear that is common in the Philippines. It is also used for other table linens, bags, mats and other clothing items, or anytime that a lightweight, but stiff and sheer fabric is needed.