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In this unit, we shall: 

≈ identify sources of fibres and their characteristics. 
≈ recognise sources of fibres and their characteristics. 
≈ pay attention to natural and artificial fibres.

Key Unit Competency: Learners should be able to identify types of fibres and explain their characteristics

INTRODUCTION

We are all aware that fibres are the basic units for all textiles, the basic building blocks of fabric. Just take a look at the dresses and shirts you are putting on. 

They are made of threads acquired out of fibres. Just try to pick a thread from a loose garment and untwist it open, you will evidently see the small fibres. 

You very well know that there is variety of different fibres in circulation from which fabrics are made. This is the reason why, when you visit a shop with clothes you see a number of different types. 

Fibres are thin, hair-like strands that are the basic units used to make fabrics textile products. 

In this unit, we should grasp the knowledge and attain skills necessary to recognise the fabric we want to acquire by relating it with its specific characteristics and assessing its suitability to specific uses. 

You are used to a variety of uses various fabrics have in our daily life. The study of Nature of Textile Fibres and Fabrics gives us the complete knowledge of sources, characteristics and uses of various fabrics available in the cloth shops. 

This knowledge will enable us to choose wisely the fabric we wish to have and make the best use of it after we have bought it.

SOURCE AND CHARACTERISTICS OF FIBRES

From our discussion and presentation, we shall note that there are two types of textile fibres:

Ž Natural Fibres 

    Plant – Linen, Cotton

    Animal – Wool, Silk,Hair

    Mineral – Asbestos 

Ž Artificial Or Manmade Fibres

    Regenerated – Viscose, Acetate, Triacetate, Lyocell 

    Synthetic – Nylon, Polyester, Acrylic, Elastane 

    Inorganic – Carbon, Glass, Metal, Ceramic

ˆ SOURCES OF NATURAL FIBRES

It is important to note that, all fibres are made up of molecules referred to as polymers. The sources of natural fibres are:

Wool polymer, which is made up of protein and produces a short fibre known as staple fibre.

Cashmere is taken from the cashmere goat which is raised in cashemere region of India , Pakistan, Mongolia and china

Linen is made from the cellulosic fibres of the flax plant

Cotton grows on bushes which do flower. The seed produced forms pods called bolls which burs open when ripe. The boll is made up of a fluffy mass of creamy white fibres that are called cotton.

Mineral fibres: fibres can be particularly strong because they are formed with a low number of surface defects . Asbestos is a common example; it is a natural fibre used in fire resistant substances. Another manufactured mineral fiber is Rockwool.

1. List two sources of textile fibres. 
2. List and describe four sources of natural fibres. 
3. How are synthetic fibres different from natural fibres? 
4. Give two examples of plants where natural fibres are obtained. 
5. Define synthetic fibres. 

ˆ SOURCES OF ARTIFICIAL OR MAN-MADE FIBRES

a) Regenerated fibres: These are made from cellulose that comes from natural sources, for example wood pulp , soya bean and milk protein. The cellulose is extracted by chemicals. Regenerated fibres are classified according to the system used to convert the cellulose into a solution that can be spun when dissolved into acetone chemical. For example viscose and acetate 

Acetate is a combination of cellulosic and acetic acid which is made by a similar process of viscose. However, unlike viscose, acetate can be dry spun. 

b) Synthetic fibres : These are all made by similar process but using different chemicals. Coal or oil is a raw material used. Simple chemicals are joined to form polymers in a process called polymerisation. These fibres are continuous filament fibres, long and always have to be spun into big rolls called yarns. The fact that they are made from laboratories using chemicals they get to be known as man-made fibres.

Nylon was the first fibre to be made entirely from chemicals and coal.

Polyster is a versatile fibre which is synthesised from oil. It has a wide range of uses.

Acrylic is made from simple chemicals derived from oil. The polymer can either be wet spun or dry spun. The feel and handle is similar to that of wool.

Elastane is made from segmented polyurethane.it has a capacity to stretch and recover and is used mostly in a blend with other fibres.

Note: Regenerated fibres and Synthetic fibres can be produced by three methods of of spinning; wet (viscose and acrylics), dry (acetate and acrylics) and melt (nylon and polyster) spinning

c) Inorganic fibres are made from naturally occurring materials that are inorganic rather than polymeric. Examples are Carbon, Glass, Metal, and Ceramic.

The process of making yarn involves the following stages 

i. Blow room processes 

ii. Carding 

iii. Combing 

iv. Drawing 

v. Roving

Blow room process: is the beginning stage in spinning process done by blow room section because of air flow. 

Carding: The fibre is combed to separate and form a silver.

Combing: Removing short fibres (noils) leaving longer fibre (top)

Roving: Process of making spun yarn from wool fleece, raw cotton or other fibres.

Drawing: Reducing of silver thickness ready for spinning.

Characteristics of natural fibres

From our observation and investigation, we shall note that, when you look around there are four main natural textile fibres, namely:

          i. cotton     ii. linen

          iii. wool      iv. silk

By characteristic, Natural fibres are usually:

Abrasion resistance - the ability to withstand wear from repeated rubbing. From good to poor: nylon, linen, acrylic, cotton, wool (coarse), silk, wool (fine), rayon, acetate.

Absorbency - All natural fibres normally contain 10% or more water, and some can absorb up to 30% of their weight in water and feel dry to the touch. Synthetic have little or no absorbency (although, several of them do absorb oil). - from best: wool, flax, hemp, silk, cotton, ramie, nylon, acrylic, polyester.

Chemical, mildew & moth resistance - ph levels in your cleaning and dyeing baths can damage some of your fibres. Below 7 is acid, and above 7 is alkaline. Wool is resistant to acids. Silk is resistant to organic acids but damaged by mineral acids. Cellulose fibres are harmed by acids - even vinegar can do some damage. Alkaline solutions can also damage protein fibres, but cellulose fibres are more resistant.

Elasticity - all fibres can be stretched - but they do not all have the same breaking point or the ability to recover from the stretch.

Flammability - wool offers the greatest resistance to fire, and other protein fibres are usually self-extinguishing. Cellulose fibres continue to glow after they are removed from the flame. Synthetic fibres vary, but range from acrylic that is so hot that it can ignite a combustible material if it drips on it, and others that have vinyl cyanide or vinyl chloride whose fumes are toxic.

Shrinkage - compare to a rubber band - it simply returns to its natural size. Shrinkage is caused by the way we spin, weave, and finish the fabric. If yarns are dipped in water or washed, and allowed to dry in a relaxed state before being woven (or knitted) they will cause less shrinkage.

Strength - length of individual fibres, and amount of twist in the yarn can help determine the strength of the yarn, but some fibres are stronger than others: in order from strongest: flax, hemp, silk, nylon, polyester, cotton, acrylic, wool, rayon.

Sunlight resistance - from good to poor: acrylic, polyester, flax, cotton, rayon, acetate, nylon, wool, silk. Not usually a problem for clothes, but for upholstery, rug and so on.

Warmth - retention of heat from high to low: silk, angora, wool, cotton, ramie, flax. Yarns can be spun to trap air and therefore be warmer. Woolen spun yarns being in that category.

Weight - from heaviest to lightest: cotton, flax, ramie, rayon, hemp, polyester, wool, silk, acrylic, nylon.

Wrinkle recovery - from good to poor: wool, silk, cotton, rayon, ramie, flax. When relaxed fibres are used then there is less tendency to wrinkle.

Cotton

Cotton from cotton plants is a cellulose fibre acquired from “bolls” (seed pods) growing on branches. Cotton can be grown in a range of colours. It constitutes most of the main textile products of China and Mexico.

It is made into a wide range of wearing apparel for example; jeans, T-shirts and towels. In fact its end uses include a wide range of apparel: blouses, dresses, skirts, pants, underwear, and linens.

Linen

Flax is the fibre name; linen is the fabric name. Linen is a fabric made from the woody stem of the flax plant. It is interesting to note that flax is the World’s oldest textile fibre, dates back to Stone Age approximately 5,000 years.

It is cellulosic fibre from stem of flax plant. Flax products include; towels, sheets and tablecloths referred to as “linens”.

The end uses of flax include: dresses, suits, jackets, home furnishings, draperies, table linens, dish towels (figure 3.1).Linen was originally used for bedding – that’s where we got the name “linens”.

Wool

Wool fibres come from the shaved hair of sheep or lambs. Also can be from Cashmere or Angora goat hair fibres. Wool is protein fibre from sheep or lambs, at times Worsted wool is higher quality with long staple fibres (over 2 inches). It is a Natural insulator. The term wool can only apply to all animal hair fibres, including the hair of cashmere or angora goat .wool can also be got from speciality hair fibres of camel, alpaca, llama, or vicuna. Wool is used for jumpers, suits and blankets. It’s end uses include: sweaters, coats, suits, jackets, skirts, socks, scarves carpets, upholstery and blankets.

Silk

Silk is a natural protein filament produced by Silkworm cocoons. These worms are used to make silk fibre, the only natural-filament fibre Silkworms do spin cocoons in filaments. The filament is a very long, fine, continuous thread. It can take as many as 500 cocoons to create 1 blouse for instance. Silk is commonly used for evening wear and ties. Silk’s end-uses include; evening gowns, wedding gowns, lingerie, scarves, neckties, curtains and decorative pillows.

Acetate

Acetate has a luxurious appearance with crisp (texture) soft hand, a wide range of colors; it dyes and prints well. It also drapes well, it shrinkage, moths, and mildew, it has a low moisture absorbency, relatively fast drying and no pilling. It is a little static. Acetate requires dry cleaning, it is rather weak, heat sensitive, poor at abrasion resistance and easily dissolved by nail polish remover (acetone).

Nylon

Nylon is used for active sportswear, fleece jackets, socks and seat belts.

Acrylic

Acrylic fibre was manufactured in the 1950’s by DuPont. It was originally used for blankets and sweaters because it resembled wool. It is now commonly used for jumpers, fleece jackets and blankets.

Polyester

Polyester is a synthetic fibre developed in the 1950’s by DuPont.

It is used for raincoats, fleece jackets, children’s nightwear, medical textiles and working clothes.

Links to other subjects:

Organic Chemistry ( Polymerisation) in Chemistry;

Polymers

Plastics as known to the general public are known to chemists as polymers. A polymer is a macro molecule which consists of small molecular units that are repeated over and over again to form a long chain.

Properties of matter and elasticity in Physics

Elastic properties of materials

In everyday conversation if someone speaks to you about an elastic body, you probably immediately think of a rubber band. A rubber band yields a great deal to a distorting force, and yet it returns to its original length after the distorting force is removed. Can you think of some biological examples of elastic bodies? In this chapter we will examine the elastic properties of materials.

Elasticity

Elasticity is a fundamental property of materials. Springs of all kinds are examples of elastic bodies. Let us consider the characteristics of a spring. We find that a spring will respond to distorting force and then return to its original shape after the distorting force is removed. Any material or body can be deformed by an applied force. If it returns to its original shape after the force is removed, it is said to be elastic. Most substances are elastic to some degree. In a technical sense a substance with a high elasticity is one that requires a large force to produce a distortion-for example, a steel sphere.