7. natural fibers
- 1. Study of Natural fibers Text book of Pharmacognosy, by T.N. Vasudevan and K.S. Laddha, vrinda publication, Page no.183-193
- 2. Introduction • Fibres may be defined as any hair-like raw material directly obtainable from animal, vegetable, or mineral source and convertible into nonwoven fabrics such as felt or paper or , after spinning into yarns, into woven cloth. • A natural fibre may be further defined as an agglomeration of cells in which the diameter is negligible in comparison with the length. • Although nature abounds in fibrous materials , especially cellulosic types such as cotton , wood, grains, and straw, only a small number can be used for textile products or other industrial purposes.
- 3. Types of Fibers • Natural – Originate from natural sources – Plant (cellulosic) or animal (protein) • Manufactured, synthetic, or man-made (terms interchangeable) – Originate from chemical sources – May also be from regenerated or recycled sources
- 4. Natural Fibers • Natural fibers are textile fibers made from plants or animals • Cellulosic (from plants) – Cotton • From cotton plants – Flax (linen) • From flax stems • Protein (from animals) – Silk • From cocoons of silkworms – Wool • From fleece (hair) of sheep or lambs
- 6. Absorbent cotton • SYNONYMS: Raw cotton, purified cotton, absorbent cotton. • BIOLOGICAL SOURCE: Epidermal trichomes of the seeds of cultivated species of The Gossypium herbaceum and other species of Gossypium (G. hirsutum, G. barbadense) freed from impurities, fats and Sterilized, belonging to family Malvaceae. • GEOGRAPHICAL SOURCE: United States, Egypt, some parts of Africa, and India. • DESCRIPTION: • Colour White • Odour Odourless • Taste Tasteless • Shape These are fine filament like that of hair, which are Soft and unicellular. • Size 2.2-4.6 cm in length and 20-35 micron diameter • CHEMICAL CONSTITUENTS: • It consists of 90% of cellulose, 7-8% of moisture, wax, fat and oil 0.5% and cell content about 0.5%. Purified cotton has almost cellulose and 6-7% of moisture. • USES: • Cotton is used as a filtering medium and in surgical dressing. Absorbent cotton absorbs blood, pus, mucus, and prevents infections in wounds.
- 7. Jute • SYNONYM: Gunny. • BIOLOGICAL SOURCE: It consists of phloem fibres from the stem of various species of the Corchorus; C. capsularis Linn, C. olitorius Linn, and other species like C. cunninghamii, C. junodi etc., belonging to family Tiliaceae. • GEOGRAPHICAL SOURCES: West Bengal and Assam. • Description: They are tall, usually annual hers, reaching to a height of 2-4 m, unbranched and if branched it has only a few side branches. The leaves are alternate, simle, lanceolate, 5- 15 cm long and a finely serrated or lobed margin. The flowers are small (1.5-3 cm in diameter) and yellow, with five petals; the fruit encloses many seeds in the capsule.
- 8. Jute • Preparation: Cut stem and tied in small bundles Kept in water for retting (10- 30 days) for separation of fibers from wood Cover with weeds to avoid direct sun contact Submerge with heavy load like breaks, stones.. Ends of stem are bitten Hold free ends of fibers and clean by jerking them in water Dry under sunlight for 2-3 days
- 9. Jute.. • CHEMICAL CONSTITUENTS: Jute fibers are compose primarily of the plant material, cellulose and lignin. Jute is composed of about 50-53% cellulose, nearly 20% of hemicelluloses and 10-11% of lignin along with other constituents like moisture NMT 12-13%, fats, wax and ash contribution to 1% each. • USES: It has a large range of use (about 1000 uses). It is listed as the second most important vegetable fibre after cotton. Jute is used chiefly to make cloth for wrapping bales of raw cotton, in the preparation of sacks and coarse cloth, they are also woven into curtains, chair coverings, carpets, Hessian cloth very fine threads of jute can be made into imitation silk and also in the making of paper. It is also used in the manufacture of tows, padding splints, filtering and straining medium. Jute is also used for the preparation of coarse bags.
- 10. Flax • Synonym: Flax (also known as common flax or linseed), • Biological source: flex consist of pericyclic fibers with the binomial name Linum usitatissimum, is a member of the genus Linum in the family Linaceae. • Discription: Cultivated flax plants grow to 1.2 m (3 ft 11 in) tall, with slender stems. The leaves are glaucous green, slender lanceolate, 20–40 mm long and 3 mm broad. • The flowers are pure pale blue, 15–25 mm diameter, with five petals. The fruit is a round, dry capsule 5–9 mm diameter, containing several glossy brown seeds shaped like an apple pip, 4–7 mm long. • Preparation: same as that of jute • Chemical constituent: 64% cellulose, 17% hemicellulose and 2% lignin • Formerly used in maufaturing of lint but now replaced by cotton
- 11. Hemp • Biological source: Pericyclic fibers of the stem of Cannabis sativa belonging to family Cannabinaceae • Preparation: similar to jute • Description: Fiber strands are ribbon like over 1.8m long. Individual fibers 35-40mm in length and 22 µ in diameter. Cylindrical with surface irregularities in the form of frequent joints, longitudinal fractures and swollen tissues. Ends of fibers are blunt and occasionally show lateral branching. Colour: yellowish, greenish, grey or dark brown. • Chemical constituens: 67% cellulose, 16% hemicellulose and small amt of lignin. • Uses: Making carpets warp, canvas, tarpaulins, webbings, sacking, twines, ropes, cables etc. No pharmaceutical use.
- 12. Silk • BIOLOGICAL SOURCE: Fibres obtained from the cocoons spun by the larvae Bombyx mori Linn., belonging to family Bombycidae/Moraceae. • GEOGRAPHICAL SOURCE: China, France , Iran, Italy, Japan, and India. • DESCRIPTION : • Colour : Yellow • Size : 5 to 25 microns in diameter and 1,200 metre in length • Appearance: Fine, solid, smooth to touch • Solubility: Soluble in cuoxam , in cold dilute sulphuric acid. • Extra features: Hygroscopic in nature and has good elasticity and tensile strength.
- 13. Silk • Preparation: • The silk moth lays thousands of eggs. • The silk moth eggs hatch to form larvae or caterpillars, known as silkworms. • The larvae feed on mulberry leaves. • Having grown and moulted several times silkworm weaves a net to hold itself • It swings its head from side to side in a figure '8' distributing the salivar that will form silk. • The silk solidifies when it contacts the air. • The silkworm spins approximately one mile of filament and completely encloses itself in a cocoon in about two or three days. The amount of usable quality silk in each cocoon is small. As a result, about 2500 silkworms are required to produce a pound of raw silk. • The silk is obtained by brushing the undamaged cocoon to find the outside end of the filament. • The silk filaments are then wound on a reel. One cocoon contains approximately 1,000 yards of silk filament. The silk at this stage is known as raw silk. One thread comprises up to 48 individual silk filaments.
- 14. Silk • CHEMICAL CONSTITUENTS: Silk mainly consists of protein known as fibrion. • Fibrion is soluble in warm water and on hydrolysis yields two main amino acids, glycine and alanine. • USES: Silk is used pharmaceutically in the preparation of sutures, sieves, and ligatures. • The ‘stiff silkworm’ (dried body in the four to fifth stage of larva, which dies due to infection of the fungus Beauveria bassiana) is used in the traditional Chinese medicine.
- 15. Wool • Biological source: Hairs from the fleece of the sheep, Ovis aries Linn. Belonging to family Bovidae • Description: Individual fibers are solid, 2-50 cm long and 5- 100µ in diameter. Fibers consist of central narrow core of rounded or polyhedral cells, surrounded by wide cortex of nucleated spindle shaped fibers. • Chemical constituent: Protein Keratin containing C, H, O, N and S. S containing protein is about 3-4% • Uses: Filtering and straining medium and for manufacturing of dressing like flannel, domette and crepe bandages
- 16. Wool• Preparation: Shearing • Hairs are removed from sheep • Greaded according to fineness Cleaning • Clean dirt and wool-grease by treatment with soap and sodium carbonate Washed • Washed in hot water • Dried and bleached with sulphur dioxide or hydrogen peroxide Carded • Carded and processed to form wool thread or yarn
- 17. Viscose rayon • SYNONYMS: Rayon, regenerated cellulose • BIOLOGICAL SOURCE: Viscose is a orange-red aqueous solution of sodium cellulose xanthogenate obtained by dissolving wood pulp cellulose in sodium hydroxide solution and treating with carbon disulphide. • DESCRIPTION: • The rayon is a white, highly lustrous fibre. Its tensile strength varies from two-third to one-and-a-half times that of cotton. When wetted, it loses about 60% of its tensile strength. It has a proportionately greater loss than is found with cotton. The fabric is a water-repellent (e.g. cotton crepe bandage). • Uses • Viscose rayon is used to manufacture fabrics, surgical dressings, absorbent wool, enzyme, and cellophane.
- 18. Viscose rayon • Preparation: • remove lignin and resisns • Washed, bleachedChemical treatment • Macerated with caustic soda • It gives alkali celluloseWood cellulose • Alkali cellulose soaked into alkali for 24 hrs • Then treated with carbon disulphideCellulose Xanthate • To remove particular matter and air bubbles by applying vacuumFiltration • Forced through spinneret as a jet with fine nozzles into a acid bathFormation of filament • Filaments are twisted to form thread • Then spun into yarnFormation of Yarn
- 19. Asbestos • It is fibrous mineral composed of magnesium silicate with some calcium silicate and small percentage of iron and aluminium. • Fibers vary in length from 1-10cm • Colour: white, yellow or green • They are unaffected by all the usual reagents used for the identification of fibers • On heating do not fuse (distinction from glass wool) • Uses: used as filtering media and making heat resistant hand gloves
- 20. Glass wool • Synonym: Glass fiber, fiber glass • Source: glass wool consists of glass spun into fine solid fibres • Description: Transperant, lustrous, hard fibers which are brittle. • Uses: use for filtration of corrosive liquids such as mineral acids. Use in heating mantles (electric)and refrigerator(Heat) as insulator.
- 21. Glass wool • Preparation: • Made from sand (Silica) • With oxides of calcium, magnesium, aluminium and boron Melting • Melted into marbles • Feeding in fiber-drawing machine Feeding • Marbles are melted and forced through small nozzles • It gives filament on cooling Filament formation