Fabrics Around Us

Written and reviewed by Anjali Sharma, Biology & Home Science faculty at UniDrill (M.Sc. Botany, Banaras Hindu University · 8 years teaching). Based on NCERT Home Science Class XI (Human Ecology and Family Sciences Part I), Chapter 5.

Why is cotton comfortable in May and wool in January?

Follow a fabric through your morning. The bedsheet you leave, the soft absorbent towel, the school dress, the stiff coarse school bag that still carries all your books: each is a fabric, and each was chosen for a different job. Fabrics give comfort and warmth, colour and style, and texture. Their behaviour depends on the fibre they are made of, the yarn, the way the fabric is built, and the finish applied afterwards. This chapter explains that chain so that you can predict how any fabric will behave, which is also what makes you a wise buyer of clothes.

Fibre, yarn, fabric: the chain

Unravel a piece of cloth and you pull out thread-like strands. These are yarns. In a woven fabric they cross at right angles, in a knitted cardigan or T-shirt they are looped through each other, and in nets and laces they are knotted. Untwist a yarn and you see tiny hair-like structures: these are fibres, the basic building blocks of fabrics. Fibres, yarns and fabrics together are called textiles or textile products. After the fabric is ready it may get finishing, a treatment that improves its appearance, feel or service.

The chain in one line: fibre → spinning → yarn → weaving, knitting and others → fabric → finishing → fabric in the shop.

What makes a good fibre?

For a fibre to be important it must be available in large quantities and be economical. The most essential property is spinnability, the ease with which a fibre can be turned into yarn and then fabric. It is the sum of length, strength, flexibility and surface structure. Consumers also look for colour, lustre, weight, moisture and dye absorption, and elasticity. Care and maintenance depend on abrasion resistance, effect of chemicals, soaps and detergents, effect of heat, and resistance to biological organisms.

Classifying fibres

Fibres are classified in four ways: by origin (natural or manufactured), by chemical type (cellulosic, protein or synthetic), by generic type (animal hair or animal secretion) and by common trade name (for example polyester, terene or dacron). By length, a fibre may be staple (short, like cotton) or filament (long, like silk and polyester).

Natural fibres are available in nature.

Manufactured (man-made) fibres. The first manufactured fibre, rayon, was commercially produced in AD 1895 and most others are products of the 20th century. The idea probably came from the wish to make something like silk. A silkworm eats mulberry leaves, digests them and spews a liquid through two holes (spinnerettes) that hardens into a filament. If a cellulose material could be treated similarly, a silk-like fibre should result. That is why rayon was long called artificial silk or "art silk". The earliest manufactured fibres changed a non-fibrous material (cotton waste, wood pulp) into fibre form. The second group is made completely from chemicals.

How any manufactured fibre is made. Whatever the raw material, the steps are the same. The raw material is converted into a liquid of the right viscosity (the spinning solution) by chemical action, dissolving, heat or a mix. The solution is pushed through a spinnerette, a thimble-shaped nozzle with many tiny holes, into an atmosphere that hardens it into fine filaments. The filaments are collected and stretched for fineness and orientation, and may be texturised to give stretch or bulk.

Beyond the textbook. For the exam: rayon is a manufactured cellulosic fibre, and nylon is the first true synthetic fibre. In reality: rayon is made from a natural raw material, wood pulp, treated with chemicals, so it is neither fully natural nor fully chemical. Fibre chemists call such fibres regenerated or semi-synthetic. Why it matters: a question that says "made from wood pulp" points to rayon, while "totally manufactured from chemicals" points to nylon or another synthetic.

Making yarn

Fibres can be used directly for surgical cotton and for stuffing pillows, quilts, mattresses and cushions. For most fabrics, though, they must become a continuous strand called yarn: a continuous strand of fibres, filaments or material suitable for knitting, weaving or intertwining into a fabric. Fabrics like felts and non-wovens are an exception, since they are made directly from fibres.

Processing natural staple fibres into yarn is called spinning, though spinning is actually the last step. The stages are as follows.

Manufactured and silk yarns. All manufactured fibres are first made as filaments. A yarn may be a single filament or a multifilament yarn, where many filaments are twisted together. Filaments may also be cut into staple length and spun like natural fibres to give spun yarns. This is how blends such as terecot (terene and cotton) and terewool (terene and wool) are made. Silk, being a filament, does not need spinning but is reeled from the cocoon. Broken filaments are spun like cotton to give spun silk.

Yarn terms.

Pause and predict: two reels of cotton thread are marked 20 and 60. Which one is finer?

Check your answer: The reel marked 60. A higher yarn number means a finer yarn.

Making fabric

A small group of fabrics is made directly from fibres, namely felts and non-wovens (bonded fibre fabrics). The fibres, after carding and combing, are laid as a mat and made to stick together, and the mat can be made in any thickness or shape. Most fabrics, however, need yarn. The main methods are weaving and knitting, and to a small extent braiding and knotting.

Weaving in detail. Weaving is the oldest form of textile art, originally used to make mats and baskets. The warp yarns are fitted on the loom, held at fixed tension and spacing, and they decide the length and width of the fabric. The filling yarn (weft) is then interlaced with them. In the simplest interlacing, the filling goes over and under one warp yarn alternately, and the process is reversed in the next row. Passing it over and under different numbers of warp yarns in a set order gives different designs. Attachments like the dobby or jacquard help to create figured designs, and different coloured yarns make the pattern clearer. An extra yarn held as loops gives texture. Uncut loops give a towel, while cut loops give velvet and corduroy.

Knitting in detail. In weft knitting (filling knitting) a series of loops is made and each row is interlooped with the previous one, with the yarn moving across the width. It is used for articles that can be shaped while being constructed. In warp knitting, which is an industrial method, a set of yarns is fitted on the machine like warp yarns and the interlooping happens with adjacent yarns. It produces continuous lengths that, unlike weft knitted fabric, can be cut and stitched. Knitted fabrics are made faster, are porous, allow free air circulation, are comfortable and allow movement, so they are ideally suited for sportswear.

Other constructions.

Finishing: what happens after the loom

A fabric straight from the loom looks nothing like the cloth in the market. All market fabrics get one or more finishes, and except for whites, colour is added. A finish is any treatment that changes the appearance, texture or behaviour of a fabric for a specific use. Finishes considered absolutely necessary are called routine. A finish is durable if it does not come off on washing or dry cleaning, like dyeing, and renewable if it must be applied repeatedly, like starching or blueing.

Colour. Dyes are substances that add colour in a way that does not easily wash out. The method depends on the chemical nature of the fibre and dye and the effect wanted. Colour may be applied at three stages.

Printing is a specialised form of dyeing in which colour is applied only to specific areas within the limits of a design. Several colours can be used. Hand tools such as blocks, stencils and screens are used, and industrially roller printing and automatic screen printing.

Fibres at a glance

This table is the heart of the chapter. Questions ask which fibre fits a property or use.

Cotton and linen in detail. Cotton fibres come from the seed pod of the cotton plant. When the pod ripens it bursts, and seeds are separated from fibres by ginning. Bales then go for spinning. Linen comes from the stems of the flax plant. The stems are soaked for a long time to rot away the soft parts, a process called retting, and the fibres are then collected. "Bast" means the fleshy part inside the bark.

Wool and silk in detail. Removing hair from a sheep is shearing, done once or twice a year, and the hair is kept in one piece called the fleece to make sorting easier. Sorted fibres are scoured to remove dirt, grease and dried perspiration. Carbonisation removes entangled vegetable matter like leaves and twigs. Wool from goats, rabbits and camels is called speciality hair fibre. Silk production is called sericulture. Cultivated mulberry silk is smooth, fine and lustrous. Wild silk is brownish, coarser, shorter and stronger, as in tussar silk. Natural silk colour is off white to cream.

Worked example: reading a blend label. A shirt-piece of 250 g is labelled 65 per cent polyester and 35 per cent cotton. Find the weight of each fibre.

The result tells you that the fabric will behave partly like polyester (wrinkle resistance) and partly like cotton (absorbency). The common wrong step is to read the two percentages as grams, which gives 65 g and 35 g and does not add up to the weight of the piece.

Two views. For the exam: India is the first country where cotton was grown and used. Another reading: archaeologists and botanists note that different cotton species were domesticated independently in different parts of the world, including South Asia, Africa and the Americas, so early cotton use is documented in more than one region. The exam answer remains India, but you should know that the question of "first" is discussed by scholars.

Matching the fabric to the use

The chapter's aim is informed selection of textile products. The choice depends on end use.

Identifying fibres by burning

Heat affects fibres differently, and the pattern of burning helps identify fibre content and shows what care a fabric needs. This is done only with a thin strip held with forceps near a very low flame under teacher supervision.

A simple way to remember the table: plant fibres smell of burning paper, animal fibres smell of burning hair, and synthetics melt into a bead.

Pause and predict: a thread curls away from the flame, burns slowly, smells like burning hair, goes out when removed and leaves a crushable ash. What is it?

Check your answer: Wool or silk. Both are protein fibres from animals, which is why they smell of burning hair and are self-extinguishing.

Beyond the textbook. For the exam: each fibre has a characteristic burning pattern. In reality: the burning test works best on pure, unfinished fibres. Blends and finished fabrics give mixed results, so textile laboratories also use microscopic and chemical tests to confirm fibre content. Why it matters: the burning test is a useful first clue, not the final proof.

Exam traps

60-second revision

Where this chapter connects

• Previous: Management of Resources lists fabrics among the material resources of daily life.
• Next: Media and Communication Technology is the other shared interest of adolescents.
• Later in the course: Our Apparel turns fabrics into clothes, and Care and Maintenance of Fabrics shows how fibre properties decide washing and storage.
• Class XII link: Design for Fabric and Apparel builds on yarn, construction and finishing.