Textile Science (FP1007) Unit 1 & 2 PDF

TEXTILE SCIEINCE (FP1007) BY MONALISA DAS FIBRE SCIENCE: UNIT-1 Classification Of Textile Fibres Sources Of Fibres Manufacturing Process Of Regenerated Cellulose Polymer Manufacturing process of Synthetic polymer. Physical and chemical properties of fibres and their...

TEXTILE SCIEINCE (FP1007) BY MONALISA DAS FIBRE SCIENCE: UNIT-1 Classification Of Textile Fibres Sources Of Fibres Manufacturing Process Of Regenerated Cellulose Polymer Manufacturing process of Synthetic polymer. Physical and chemical properties of fibres and their uses- cotton, Jute, Flax, Wool, Silk, Viscose, Nylon, Polyester, Acrylic, Polypropylene etc. TEXTILE FIBER Textile Fiber is a smallest part of the fabric. This single hair like strand of fabric is called a fiber.  Textile fiber can be spun into a yarn or made into a fabric by various methods including weaving, knitting, braiding, felting, and twisting. The essential requirements for fibers to be spun into yarn include a length of at least 5 millimeters, flexibility, cohesiveness, and sufficient strength. Other important properties include elasticity, fineness, uniformity, durability, and luster.  Textile fiber has some characteristics which differ between fiber to Textile fiber. They are the basic building block used in manufacturing fabric. It can be called a body that is very long in relation to the thickness. FIBER SCIENCE Fiber Science is the study of the formation, structure, and properties of fibers on micro to macroscopic levels. The study of fibrous materials and their use in a variety of conventional and non-conventional applications. APPLICATION OF TEXTILE FIBERS Uses of Textile fibers & fabrics Apparels Home furnishings / Home textiles Technical textile/Industrial Textile Example: Blouses, trousers, Shirts, saris and skirts Examples: Bandage, Filters, ropes, luggage and Parachutes Examples: Sofa cover, Cushion covers, Curtains and Carpets TEXTILE FIBRE CLASSIFICATION CHART AND VARIOUS TYPES OF TEXTILE FIBRES CLASSIFICATION OF TEXTILE FIBRES: Textile fibers have been used to make cloth for several thousand years. First manufactured fiber was produced commercially on 1885 and was produced from fibers of plants and animals. Wool, flax, cotton and silk were commonly used textile fibers. Textile fibers are characterized by the flexibility, fineness and large length in relation to the maximum transverse dimension. On the basis of origin fibers can be classified broadly into three types: Natural fibres. Man-made fibres. Re-generated fibres. NATURAL FIBRES: “Textile fibres directly obtained from nature are called natural fibres”. These fibres can not be produced by any type of chemical process. Natural fibres further can be classified in two categories according to its source of generation. 1-animal fibres: wool , silk, spider silk,rabbit hairs,camel hairs, goat hairs, yak. 2-vegetable fibres: cotton,linen,jute,hemp,banana,kopok,kenaf,remie,raffia,sisal,coir,etc. MAN-MADE FIBRES OR SYNTHATIC FIBRES: “Textile fibres produced by human through one or more types of chemical process are called man-made or synthetic fibres”. These fibres are produced in laboratory and in industrial manufacturing units. These fibres are produce by polymerization of a monomers of chemical compounds. Few common examples are polyester, nylon, acrylic, polypropylene, elastane ,poly vinyl acetate, poly vinyl alcohol, poly vinyl chloride, polythene, poly urethene etc. RE-GENERATED FIBRES: These fibres can neither directly found from nature nor can be produce by using chemical. “these fibres are re- generated from natural material using some chemical process”. Monomers are obtained by treating natural material with chemicals. common examples are rayon, bamboo fibres, modal,lyocell ete. Stem Leaf Seed Husk  Monomer Cotton polymer: Cellulose Introduction Textile fibers are made by man starting from various kinds of raw materials. The starting raw materials for fiber making can be natural and synthetic polymers. Accordingly man- made fibers are classified in to regenerated and synthetic. Basic Principle In Fiber Manufacturing Conversion of the fiber-forming substance into a fluid solution or melting. Extrusion of the fluid through spinnerets. Solidification of the extruded filaments TECHNOLGY OF MAN MADE FIBERS The technology of man made fiber manufacturing --- SPINNING A spinneret (perforated plate) may have from one to several hundred holes. Monofilament: when the spinneret has only single hole Multi-filament: the bunch of filaments from a multi-hole spinneret. Spinneret hole may be circular or some other shape based on requirement. This enables production of filaments having different cross-section. Manufacturing of fiber forming polymer: Synthetic fiber-forming polymers are made in two steps: 1. Synthetic of reactive precursors: These are small molecules, which are called monomers. Petroleum is the main raw material for their production. 2. Coupling: It is a process to form macro molecules from of thousands of monomers. The macromolecules are called linear polymers, because they are built from many monomers into long chains. This process is named as polymerization. Polymerization: Polymers are very large molecules made up of smaller units called monomers or repeating units, covalently bonded together. Two different types of polymerization reaction are utilized to synthesize fiber-forming polymers. Namely: 1. Addition: Addition polymers are made by direct coupling of two, usually identical. Reactive monomers to form long chains, without by-product. Typical addition polymers are polyacrylics, polyvinyl chloride and polypropylene. 2. Condensation: Condensation polymers are made by coupling two. Usually different, reactive monomers, with the elimination of a small by-product molecule. Typical textile condensation polymers are polyesters and polyamides.. There are three major types of process for manufacturing manmde fibers. 1. Melt spinning. 2. Wet spinning. 3. Dry spinning Melt spinning: The molten polymer is extruded through spinneret then passed into cold air stream which cools the soft melted fiber and solidifies the filaments. Later solidified filament is drawn at 3 to 8 times for specific fineness. Examples: Nylon, Polyester. Wet spinning: The polymer solution is extruded into a bath containing chemicals which neutralize the solvent and coagulate the filaments. According to fineness of filaments, solid filament is drawn certain times. Examples: Viscose, Acrylics. Dry spinning: The polymer solution is extruded through spinneret into a stream of warm air which evaporates the volatile solvent and solidifies the filaments. According to fineness of filament, solid filament is drawn a certain times. Examples: Acrylics, Acetate. They have several basic elements in common: a reservoir and a metering pump for the fiber-forming material, a spinning jet, a fluid by which the filaments are formed and a take-up mechanism which draws the filaments and winds them onto a package. After the filaments have been extruded and solidified, they are drawn out between rollers having different speeds. Drawing can also be a separate process. Spinneret size, plus spinning and drawing conditions, determine the final filament diameter. COTTON FIBER Introduction Cotton referred to as the “King of fibers” is most important textile fiber in the world. Cotton is a vegetable fiber which surrounds the seeds of the cotton plant. Cotton has been cultivated for more than 5000 years. Cotton plant belongs to the family “GOSSYPIUM”. The cotton fiber is made up of countless cellulose molecules. Cotton is removed mechanically from the seed bolls by the cotton ginning. The ginned cotton is then pressed into bales and sent to the factories to be spun into yarns. STRUCTURE OF COTTON FIBER Ginning Process After picking, the cotton fibers have to be separated from the seeds by the process of Ginning. Generally two types of Ginning methods: 1. Saw Ginning 2. Roller Ginning BY-PRODUCTS OF COTTON The raw cotton passes through several cleaning processes before it is baled. As a result, the grower obtains valuable by-products that amount approximately to one-sixth of the entire income derived from the cotton plant. Cotton Linters: Short hair like fibers used in making Regenerated fibers Hulls: Outside portion of seed, rich in nitrogen, used as fertilizer Inner Seeds: Seed inside the hull gives cottonseed oil, used in cooking and making soap. PROPERTIES & USES Chemical Properties of cotton Fiber Physical Properties of Cotton Fibre: Action with alkali:Here, preventive power is good. Alkali does not damage cotton fibre. 1. Length: 0.5ʺ - 2.5” Action with acid: Strong acid damage the fibres. 2. Strength, tenacity (gm per Concentrated sulphuric acid and hydrochloric acid denier): 3 – 5 damage the fibre. But weak acid does not damage 3. Dimensional stability: medium the fibre. 4. Heat preventive power: medium Action with bleaching:No damaging event is 5. Moisture regain: 7-10% (standard occurred here. Cotton is converted into oxi- 8.5%) cellulose in strong oxidizing bleaching. 6. Stiffness: 57-60 g/d due to high Dye ability:Affinity to color is good. Direct, crystallinity reactive, sulphur and vat dyes are used. 7. Elasticity: 1.50- 1.58 Heat: Conductive ironing temperature is 150°C 8. Resiliency: low where decompose is 2400°C and ignition 9. Abrasion resistance: medium temperature is 390°C. 10. Density (gm/cc): less than both Action with organic solvent: Resistance so dry is silk and wool but more than linen. possible here. 11. Color: cream or yellowish like Sunlight preventive power: Ultraviolet ray converts clean white. the cotton into oxi-cellulose. 12. Specific gravity: 1.52-1.55 Mildew preventive power: Untreated not easy. There is possibility to be affected. Insects preventive power: Not affected by moth. Characteristics of Cotton Fibers and Products 1. Comfortable to wear 2. Natural, cellulosic fiber 3. Made from the cotton boll 4. Absorbs water and “breathes” 5. Slow to dry 6. Resists static electricity build-up 7. Wrinkles easily 8. Can withstand heat, detergents, and bleach 9. About 20% stronger when wet than dry 10. Will shrink unless treated 11. Can be damaged by mildew 12. Can be damaged by prolonged exposure to sunlight 13. Long staple cotton (such a Supima, Pima, Egyptian, and Sea Island) can be woven into smooth, almost silky fabrics. End Uses: The fibers are sent to a textile mill where carding machines turn the fibers into cotton yarn. The yarns are woven into cloth that is comfortable and easy to wash but does wrinkle easily. Cotton fabric will shrink about 3% when washed unless pre-treated to resist shrinking. Cotton is prized for its comfort, easy care, and affordability and is ideal for clothing, bedding, towels, and furnishings. JUTE FIBERS Introduction: Jute is known as golden fibre because of its golden color & it will bring a golden future for Bangladesh. Jute is a bast fiber used for sacking, burlap, and twine as a backing material for tufted carpets. It is one of the cheapest and the strongest of all natural fibers and considered as fiber of the future. Jute occupies second place next to cotton in worlds production of natural fibre. CHEMICAL PROPERTIES OF JUTE Application jute fibre: FIBRE: 1. Industrial textile PHYSICAL PROPERTIES OF Tarpaulin JUTE FIBRE: 1. Prolonged heating causes Jute geotextile 1. Fibre length - 50 to 300 mm degradation of jute fibre. 2. Apparel textile 2. Fibre diameter - 0.035 to 0.14 2. Action of heat - strong acid at outerwear mm boiling causes hydrocellulose suits 3. Specific gravity - 1.48 gm/cc 4. Fibre denier - 6 to 50 and lead to loss in strength. But hessian cloth 5. Tenacity - 2.7 to 5.3 gm/tex dilute acid have no effect on jute 3. Home textile 6. Breaking elongation - 0.8 to fibre. floor covering 1.8 % 7. Moisture regain - 13 % 3. Action of alkali- Dilute alkali has carpets 8. L:D - 110 to 140 no effect of jute fibre, but strong upholstery 9. Unit cell length 0.8 to 6 mm alkali at boil causes loss in chair covering 10. Traverse swelling in water - strength. curtains 20 to 22 % FLAX FIBRE Flax is bast fibre found in stem of the plant “Linum usitatissimum”. Textile made from flax in western country are known as linen, and traditionally used for bed sheet, under cloth and tablecloth. Word “FLAX” refer to unspun fibre of flax plant. The fibres from bundles or strands that are present in fibrous layer lying beneath the bark of the plant. In inner bark of this plant there are long, slender, thick- walled cells of which fibre strand are composed. Flax plants grows to a height of about 0.5 to 1.25 meter. Stem has diameter between 1.6 to 3.2 mm. Seeds in plants are contained in small spherical balls, at the top of the stalks; this is called the linseed, from which linseed oil is produced. Flax is cultivated in cold and humid condition. Major source of flax is from old USSR, other countries having flax growing area are Egypt, Japan, Argentina, Brazil, France, USA, Canada, Australia etc. PHYSICAL PROPERTIES OF FLAX FIBER : CHEMICAL PROPERTIES OF FLAX FIBER: Effect of acids: flax fiber is easily Length : The average length of flax fiber damaged by high concentrated acids. But varies from 90-125 centimeters. The length it is not affected by low dense acids if of individual fiber cells varies from 6-65 mm washed immediately. with an average diameter of 0.02mm. Effect of alkalis: Flax fiber has an Color: Brownish, ivory, grey, light, yellowish. excellent resistance to alkalis. It is not Tensile strength: Tenacity varies from 6.5 to degraded by strong alkalis. 8 gm/denier. Effects of bleaches: Cool chlorine and Elongation: Elongation at break is hypo chloride bleaches doesn’t affect flax approximately 1.8 % (dry) and 2.2% (wet). fiber. Specific gravity: 1.54 Dyes: It is not suitable for dyeing. But it Effect of moisture: M.R = 12% (std) can be dyed by direct or vat dyes. Effect of heat: Highly resistant to decomposition up to 120C. The fibers begin to discolor after crossing temperature limit. Heat conductance is good. Abrasion resistance: Moderate Dimension stability: Good but tends to crease easily. USES AND APPLICATION OF FLAX FIBER : Flax fiber is used to produce linen fabrics. The uses of linen have changed dramatically since 1970. 70% of linen produced in 1990 was used in apparel textiles. It also has various applications. Such as- 1.Table wear 2.Suiting 3.Surgical thread 4.Sewing thread 5.Bed linen 6.Kitchen towels 7.High quality papers 8.Handkerchief linen 9.Shirting 10.Draperies 11.Wall covering 12.Artist’s canvases 13.Luggage fabrics 14.Paneling 15.Insulation 16.Filtration 17.Fabrics for light aviation 18.Automotive end uses 19.Composite boards WOOL FIBER Wool fiber is the natural hair grown on sheep and is composed of protein substance called as keratin. Wool is composed of carbon, hydrogen, nitrogen and this is the only animal fiber, which contains sulfur in addition. The wool fibers have crimps or curls, which create pockets and give the wool a spongy feel and create insulation for the wearer. The outside surface of the fiber consists of a series of serrated scales, which overlap each other much like the scales of a fish. Wool is the only fiber with such serration’s which make it possible for the fibers to cling together and produce felt. END USES OF WOOL: 1. Knitted apperals, 2. Suiting, over coat, sweater, 3. Carpet, lining fabric, 4. Lustrous dress, 5. Designs for kurtain, 6. Blanket, 7. Hosiery fabric, 8. Home uses furnishing fabric PROPERTIES OF WOOL FIBER: CHEMICAL PROPERTIES OF WOOL FIBER: For processing wool fiber, we should know about properties of wool fiber. Now I have Effect of Acids: Wool is attacked by hot discussed the following properties of wool concentrated sulphuric acid and fiber. decomposes completely. 1. Physical properties of wool fiber Effects of Alkalis: The chemical nature of 2. Chemical properties of wool fiber wool keratin is such that it is particularly sensitive to alkaline substances. Wool will PHYSICAL PROPERTIES OF WOOL FIBER: dissolve in caustic soda solutions that Specific Gravity: 1.31 would have little effects on cotton. Strong Length : 35 to 250 mm alkaline affect on wool fiber but weak Color: The color of wool fiber could be white, near alkaline does not affect wool. white, brown and black. Effect of Resilience: Wool fibers can be Flame reaction : Odor of burnt horn stretched up to 50 percent of their original Luster: Luster of course fiber is higher than fine length when wet and 30 percent when dry. fiber. Effect of Organic Solvent: Wool does not Moisture Regain: 13-16% , very absorbent, affect in organic solvents. decrease strength when wet, seem warmth, Effects of Insects: Wool affected by insects. will shrink in washing. Effect of Micro Organism: It is affected by Elongation at break: Standard elongation is 25 – mildew if it remains wet for long time. 35% and 25 – 50% in wet condition. Dyeing ability: Wool absorbs many Feel or Hand: Soft. different dyes deeply, uniformly and directly Resiliency: Excellent (due to crimp) without the use of other chemicals. Abrasion resistance: Good. Because of this ability, wool is known for Effect of Heat: Heat affects the wool fiber greatly. the beautiful, rich colors that can be Effect of Sun Light: The fibers become discolored achieved. and develop a harsh feel. SILK Silk is a natural protein fiber. It is manufactured by the silkworm which produces the cocoon. This type of fiber is extracted from a cocoon. Makes a soft, supple, strong and lightweight fabric, warm and sheer. Silk is the strongest natural fiber, makes sheer yet durable fabrics and can be blended with many fibers, including cotton and wool. The process of unwinding the filament from the cocoon is called reeling. 3 to 10 strands are reeled at a time depending on the diameter of the yarn required. The usable length of the reeled filament is 300 – 600 mt. Short lengths of inferior silk filaments obtained from the waste material are carded, combed and spun into yarn much like cotton or linen. Spun silk fabric tends to become fuzzy because of the short staple. For 100% spun silk the yarn count definition is the same as cotton the Ne being the number of yarn hanks each 840 yards long which make one pound of yarn. Types of Silk Fiber in Textile: Silk is mainly of two types. One is cultivated silk and the other one is wild silk. There is much more variation in the physical properties of wild silk than there is in cultivated silk. Color, for example, may be yellow, grey, brown or green. Seen under the microscope, wild silk may be distinguished from cultivated silk by its irregular width. It is also marked by longitudinal striations ( ridges) and tends to have flattened areas on which are transverse markings. These flattened areas are caused by filaments pressing against one another in the cocoon before the material of the silk has hardened. Treatment of the wild silk filament with chromic acid will disintegrate it into a bunch of finer filaments, fibrils or micelles about one micro in diameter. The same effect can be obtained by severe mechanical or chemical treatment of cultivated silk, in which the fibrils are more closely compacted. Cultivated silk is better than wild silk in the textile industry. PHYSICAL PROPERTIES OF SILK FIBER: PHYSICAL PROPERTIES OF SILK: CHEMICAL PROPERTIES OF SILK: 1. Silk is one of the strongest 1. Silk emitted by the silkworm natural fibers, but it loses up consists of two main proteins, to 20% of its strength when sericin and fibroin. wet. 2. It has a good moisture 2. fibroin being the structural regain of 11%. center of the silk, and serecin 3. Its elasticity is moderate to being the sticky material poor: if elongated even a surrounding it. small amount, it remains stretched. 3. Silk is resistant to most mineral 4. It can be weakened if acids, except for sulfuric acid, exposed to too much which dissolves it. sunlight. 5. It may also be attacked by 4. It is yellowed by perspiration. insects, especially if left dirty. 6. Silk is a poor conductor 5. Chlorine bleach will also of electricity and thus destroy silk fabrics. susceptible to static cling. APPLICATIONS 1. Clothing:Silk's absorbency makes it comfortable to wear in warm weather and while active. Its low conductivity keeps warm air close to the skin during cold weather. 2. Furniture: Silk's attractive lustre and drape makes it suitable for many furnishing applications. It is used for upholstery, wall coverings, window treatments (if blended with another fiber), rugs, bedding and wall hangings. 3. Industry: Silk had many industrial and commercial uses, such as in parachutes, bicycle tires, comforter filling and artillery gunpowder bags. 4. Medicine : A special manufacturing process removes the outer sericin coating of the silk, which makes it suitable as non-absorbable surgical sutures. This process has also recently led to the introduction of specialist silk underclothing, which has been used for skin conditions including eczema. VISCOSE FIBRE Viscose fibre is developed from a grouping of natural and man-made constituents and it can be made into the more ordinary form of rayon, it is used in several kinds of textile materials such as clothing, upholstery….. Properties and Uses: Viscose gives the appearance and feels as soft and silky Viscose has the aptitude to respire in a wary similar to cotton Viscose fibres have good moisture regain property like cotton fibres Viscose fibres can be easily dyed in several colors When heating the viscose fibre, it does not shrink Viscose fibre is biodegradable Viscose can be blend with some other fibres: with polyester gives Polyviscose, with cotton give Cotton-Viscose Also viscose can be blend with spandex for good stretch ability Viscose can be used in several industries such as Apparel Industry, hygienic disposables where its higher absorbency is of great advantage Viscose is an excellent material for linings in filament yarn structure Viscose can be used very little in home furnishing fabrics but in the industrial field, it is the main product used in European market to redevelop rapid tyres because of its thermal stability. Viscose can crease easily and minimize in its size when introduced in hot water. Viscose has a good drape-ability property. NYLON TYPES OF NYLON Nylon is the most useful synthetic material with Nylon 6 – It was developed by Paul applications varying from daily life activities to Schlack. It is formed by ring-opening industries. It is a plastic which can be drawn into polymerization. fibres or moulded into daily products for making Nylon 510 – It is obtained from sebacic amenities. We can live our entire life with nylon on and pentamethylene diamine acid. our side. You hop across the nylon carpet to the Nylon 1,6 – It is produced from kitchen, eat your breakfast on a nylon bowl after dinitriles with the help of acid cleaning your teeth with a toothbrush whose bristles are made of nylon. A nylon umbrella over your head catalysis. is used to move out of the house in heavy sunlight or Nylon 66 – Wallace Carothers to keep out of the rain. Nylon is very much suitable patented nylon 66 with the use of for hosiery and the knitted fabrics because of its amide. smoothness, light weight and high strength. Nylon is USES OF NYLON a lustrous fibre. The lustre of the fibre can be modified by adding the delustering agent at the Clothing – Shirts, Foundation molten stage. garments, lingerie, raincoats, PROPERTIES OF NYLON underwear, swimwear and cycle wear. 1. Lustrous 2. Elastic Industrial uses – Conveyer and seat 3. Very strong belts, parachutes, airbags, nets and 4. Damage resistant to oil and many chemicals ropes, tarpaulins, thread, and tents. 5. Resilient It is used to make a fish net. It is used 6. Does not absorb water as plastic in manufacturing machine 7. Dries quickly parts PHYSICAL AND CHEMICAL PROPERTIES NYLON FABRICS PHYSICAL PROPERTIES NYLON FABRICS: Strength: Nylon has good tenacity and the strength is not lost with age. Nylon has a high strength to weight ratio. It is one of the lightest textile fibres is at the same time also one of the strongest. It is one of the fibres which are added at the points of wear such as knees and seats of jeans and toes and heels of socks. The strength of the nylon fabric is lost when wet. Nylon has excellent abrasion resistance. Elasticity: Nylon has good elasticity which makes it much suitable CHEMICAL PROPERTIES NYLON FABRICS for the apparel purposes. The excellent elasticity would mean that the nylon materials return to their original length and shreds the Composition: The nylons are polyamides with recurring amide groups. wrinkles or creases. They contain carbon, oxygen, nitrogen and hydrogen elements. Resilience: Nylon fabrics have excellent resilience. Nylon fabrics Effect of Bleaches: The nylon fabrics are white and generally do not retain their smooth appearance and the wrinkles from the usual require bleaching. The nylon fabrics which pick up colour or develop daily activities can be removed easily. greying should be bleached with oxidising bleaches such as hydrogen Cleanliness and Washability: Nylon fabrics are easy care peroxide. garments. Nylon fabrics are smooth, non-absorbent and dry Shrinkage: Nylon fabrics retain their shape and appearance after quickly. Dirt doesn’t cling to this smooth fibre, which can be washing. It has good stability and does not shrink. washed easily or can be even cleaned by using a damp cloth. Effect of Heat: Nylon should always be ironed at low temperatures. Absorbency: Nylon fabrics have low absorbency. The low Using hot iron will result in glazing and then melting of the fabric. absorbency of the fabrics tends to be advantageous and also Effect of Light: Nylon fabrics have low resistance to sun light. They are disadvantageous. The main advantage of the nylons low not suitable for curtains or draperies as it is weakened by the absorbency is that the water remains on the surface of the fabrics exposure to sun light. and runs off the smooth fabric and hence dries quickly. This Resistance to Mildew: Nylon fabrics have absolute resistance to the property makes the nylon fabrics suitable for raincoats and development of mildew. shower curtains. Resistance to Insects: Nylon is resistance to the moths and fungi. Drapability: Fabrics of nylon filament yarn have excellent draping Reaction to Alkalis: Nylon has excellent resistance to alkali's but the qualities. The drape of the fabrics made from nylon can be varied frequent and prolonged exposures to alkalis will weaken the nylon depending on the yarn size. fabrics. Cleanliness and Washability: Nylon fabrics are easy care Reaction to Acids: Nylon is less resilient to the action of acids and is garments. Nylon fabrics are smooth, non-absorbent and dry damaged by strong acids. quickly. Affinity for Dyes: Nylon can be easily dyed with a wider range of dyes. Heat Conductivity: The heat conductivity of the nylon fabrics vary The dyed fabrics retain their colour and have good resistance to depending upon the fabric construction, the type of nylon fading. (staple/filament) used in the construction etc. Resistance to Perspiration: Nylon fabrics are resistant to perspiration. POLYESTER FIBER AND ITS USES The fabrics made from polyester fibre have good elasticity, wrinkle resistance, shape retention, excellent wash-and- wear performance and durability, and so on so that it is widely used in all kinds of apparel fabrics. However, because polyester fibre is poor in moisture absorption, its clothing makes the wearer feel hot and sticky, produces static electricity easily which results in clothing absorbing dust and clinging to the body, and has poor comfort. Manufacturing Polyester is the most commonly used synthetic fibre. DuPont introduced its Dacron brand of polyester in 1951, but the material itself was patented earlier in 1941. It’s made by reacting dicarboxylic acid with a dihydric alcohol. This base material can be used to make many things, from soda bottles to boats, as well as clothing fibres. Like nylon, polyester is melt-spun – this process allows the fibres to be made in different shapes and sizes for specific applications. Chemists can now alter the size and shape of polyester fibres to look and feel more like natural fibres. Ultra-thin microfibers can give polyester a smoother, softer feel than the polyester of twenty years ago. PROPERTIES OF POLYESTER FIBRES CHEMICAL PROPERTIES PHYSICAL PROPERTIES MOISTURE REGAINS: The moisture regain of polyester is low, EFFECT OF ALKALIES: Polyester fibres have good resistance to weak ranges between 0.2 to 0.8 per cent. Although polyesters are alkalies high temperatures. It exhibits only moderate resistance to non-absorbent, they do not have wicking ability. In wicking, strong alkalies at room temperature and is degraded at elevated moisture can be carried on the surface of the fibre without temperatures. absorption. EFFECT OF ACIDS: Weak acids, even at the boiling point, have no SPECIFIC GRAVITY: The specific gravity 1.38 or 1.22 depending effect on polyester fibres unless the fibres are exposed for several on the type of polyester fibres is moderate. Polyester fibres days. Polyester fibres have good resistance to strong acids at room have a density greater than polyamide fibres and lower than temperature. Prolonged exposure to boiling hydrochloric acid rayon. Fabrics made from polyester fibres are medium in destroys the fibres, and 96% sulfuric acid and causes disintegration weight. of the fibres. HEAT EFFECT: The melting point of polyester is close to that of EFFECT OF SOLVENTS: Polyester fibres are generally resistant to polyamide, ranging from 250 to 300°C. Polyester fibres shrink organic solvents. Chemicals used in cleaning and stain removal do from flame and melt, leaving a hard black residue. The fabric not damage it, but hot m-cresol destroys the fibres, and certain burns with a strong, pungent odour. Heat setting of polyester mixtures of phenol with trichloromethane dissolve polyester fibres. fibres, not only stabilizes size and shape but also enhances Oxidizing agents and bleachers do not damage polyester fibres. wrinkle resistance of the fibres. ACRYLIC FIBER: A manufactured fiber in which the fiber-forming substance is any long chain synthetic polymer composed of at least 85% by weight of acrylonitrile units. Acrylic fibers are produced by two basic methods of spinning (extrusion), dry and wet. In the dry spinning method, material to be spun is dissolved is a solvent. After extrusion through the spinneret, the solvent is evaporated, producing continuous filaments which later may be cut into staple, if desired. In wet spinning, the spinning solution is extruded into a liquid coagulating bath to form filaments, which are drawn, dried, and processed. PROPERTIES OF ACRYLIC FIBERS 1. Acrylic has a warm and dry hand like wool. Its density is 1.17 g/cc as compared to 1.32 g/cc of wool. It is about 30% bulkier than wool. It has about 20% greater insulating power than wool. 2. Acrylic has a moisture regain of 1.5-2% at 65% RH and 70 deg F. 3. It has a tenacity of 5 gpd in dry state and 4-8 gpd in wet state. 4. Breaking elongation is 15% ( both states) 5. It has a elastic recovery of 85% after 4% extension when the load is released immediately. 6. It has a good thermal stability. When exposed to temperatures above 175 deg C for prolonged periods some discolouration takes place. 7. Acrylic shrinks by about 1.5% when treated with boiling water for 30 min. 8. It has a good resistance to mineral acids. The resistance to weak alkalies is fairly good, while hot strong alkalies rapidly attack acrylic. 9. Moths, Mildew and insects do not attack Acrylic. 10.It has an outstanding stability towards commonly bleaching agents. USES OF ACRYLIC FIBER 1. Knit Jersey, Sweater, blankets 2. Wrinkle resistant fabrics. 3. Pile and Fleece fabrics 4. Carpets and rugs. POLYPROPYLENE Polypropylene is a 100% synthetic fiber which is transformed from 85% propylene. The monomer of polypropylene is propylene. Polypropylene is a by-product of petroleum. Polypropylene chips can be converted to fiber/filament by traditional melt spinning. USE: PHYSICAL PROPERTIES: 1. Polypropylene is a major polymer 1. Tensile strength (gf/den): 3.5 to 5.5 2. Elongation (%) : 40 to 100 used in nonwovens, with over 50% 3. Abrasion resistance: Good used for diapers or sanitary 4. Moisture absorption (%) : 0 to 0.05 products. 5. Softening point (ºC): 140 6. Melting point (ºC): 165 2. Other uses include filters for air, 7. Chemical resistance Generally: excellent gas, and liquids. Such applications 8. insulation Excellent Resistance to mildew, moth could be seen in the house as water Excellent filters or air-conditioning-type filters. CHEMICAL PROPERTIES 3.The high surface area and naturally Effect of Acids: Excellent resistance to most acids except oleophilic polypropylene nonwovens chlorosulphonic and concentrated sulfuric acid. are ideal absorbers of oil spills with Effect of Alkalis: Excellent resistance with the exception of some the familiar floating barriers near oil oxidizing agents. Effect of Bleaches and Solvents: Excellent resistance. spills on rivers. However, chlorinated hydrocarbons cause swelling at room temperature 4. Polypropylene is also used in and dissolve polypropylene at 71 °C. and higher. warm-weather clothing, which Organic Solvent Organic solvent does not cause harm during action. Protection ability against light It looses energy in sunlight. transports sweat away from the skin. Protection ability against mild dew Good. 5. Polypropylene has been used in Protection ability against insects It does not get affected by insects. Dyes hernia and pelvic organ prolapse Difficult to dye polypropylene because its moisture regain is 0%. But pigment dye is possible. repair operations to protect the body from new hernias in the same location.