Introduction

Textiles have such an important bearing on our daily lives that everyone should know something about the basics of fibres and their properties.

Textile fibres are used for a wide range of applications such as covering, warmth, personal adornment and even to display personal wealth.

Textile technology has come a long way in meeting these requirements. A basic knowledge of textile fibres will facilitate an intelligent appraisal of fibre brands and types and help in identifying the right quality for the application.

This bulletin covers various textile fibres and the properties that are important for a suitable textile application.

Fibre Classification

Textile fibres can be broadly classified into two categories:

• Natural fibres
• Man-made fibres
• Natural Fibres
• Natural fibres are subdivided further, as outlined below, by their origin.
• Table below when available.
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Man-made Fibres

Man-made fibres are subdivided as shown below with their various compositions and origin. 

1. Natural Fibres

Cotton

Cotton, the natural fibre most widely used in apparel, grows in a boll around the seeds of cotton plants. A single fibre is an elongated cell that is a flat, twisted, hollow, ribbon-like structure.

Characteristics

• Fair to good strength
• Very little elasticity
• Less resilient and prone to wrinkling
• Comfortable and soft feel
• Good absorbency
• Conducts heat well
• Damaged by insects, mildew, rot and moths
• Weakened by extended sunlight exposure

Applications

• Widely used in number of textile products
• Commonly used in woven and knitted apparel
• Home textile – bath towels, bath robes, bed covers etc.
• Used as a blend with other fibres as rayon, polyester, spandex etc.

Linen

Linen, one of the most expensive natural fibres, is made from the flax plant. It is labour-intensive to produce, hence produced in small quantities. However linen fabric is valued for its exceptional coolness and freshness in hot weather.

It is composed of 70% cellulose and 30% pectin, ash, woody tissue and moisture.

Characteristics

• Strongest vegetable fibre
• Poor elasticity, hence wrinkles easily
• Relatively smooth, becomes softer when washed
• Highly absorbent
• Good conductor of heat and feels cool
• Lustrous
• More brittle, constant creasing in the sharp folds, tends to break
• Damaged by mildew, perspiration and bleach
• Resistant to moths and carpet beetles

Applications

• Apparel – suits, dresses, skirts, shirts etc.
• Home and commercial furnishing items – table cloths, dish towels, bed sheets, wallpaper / wall coverings, window treatments etc.
• Industrial products – luggage, canvas etc.
• Used as blend with cotton

Wool

Wool fibre grows from the skin of sheep and is a relatively coarse and crimped fibre with scales on its surface. It is composed of protein. The fibre appearance varies depending on the breed of the sheep. Finer, softer and warmer fibres tend to be with more and smoother scales. Thicker, less warm fibres have fewer and rougher scales. Normally, the better wool fibres with finer scales are duller in appearance than the poorer quality fibres which have fewer scales.

Characteristics

• Crimped in appearance
• Elastic
• Hygroscopic, readily absorbs moisture
• Ignites at a higher temperature than cotton
• Lower rate of flame spread, heat release and combustion heat
• Resistant to static electricity

Applications

• Clothing – jackets, suits, trousers, sweaters, hats etc.
• Blankets, carpets, felt and upholstery
• Horse rugs, saddle cloths

Silk

Silk is a fine, continuous strand unwound from the cocoon of a moth caterpillar known as the silkworm. It is composed of protein. It is very shiny due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles.

Characteristics

• Lustrous, smooth and soft texture and not slippery
• Lightweight, strong, but can lose up to 20% of its strength when wet
• Elasticity is moderate to poor. If elongated, it remains stretched
• Can be weakened if exposed to too much sunlight
• May be affected by insects, especially if left dirty
• Can regain up to 11% of its moisture

Applications

• Shirts, ties, blouses, formal dresses, high-fashion clothes
• Lingerie, pyjamas, robes, dress suits and sun dresses
• Many furnishing applications
• Upholstery, wall coverings, and wall hangings

Other Natural Fibres

Jute

Jute is taken from a tall plant of the same name and it is easy to cultivate and harvest. It is the cheapest fibre and is used in great quantities.

Characteristics

• It is not durable as it deteriorates rapidly when exposed to moisture
• Less strength
• Cannot be bleached to make it pure white due to lack of strength

Applications

• Binding threads for carpets, coarse and cheap fabrics, heavy bagging etc.

Kapok

It is a white hair-like fibre obtained from the seed capsules of plants and trees called Ceiba Pentandra grown in Java and Sumatra (Indonesia), Mexico, Central America and the Caribbean, Northern South America and tropical West Africa.

It is called silk cotton due to its high lustre which is equal to that of silk.

Characteristics

• Smooth texture
• Very lustrous
• Weak
• Short fibre length
• Resistant to moisture, dries quickly when wet

Applications

• Mattresses, cushions, upholstered furniture

Ramie

A woody fibre resembling flax and it is also known as rhea and China grass. It is taken from a tall flowering plant.

Characteristics

• Stiff
• More brittle
• Lustrous

Applications

• Canvas, upholstery, clothing, etc.

2. Man-made Fibres

2.1. Man-made (Regenerated)

Cellulosic

They are derived either from the cellulose of the cell walls of short cotton fibres that are called linters or, more frequently from pine wood. There are three types of man made cellulosic fibres: Rayon, acetate and tri-acetate.

Rayon

Rayon [link to Raylon] is made from naturally occurring polymers that simulate natural cellulosic fibres. It is neither a truly synthetic fibre nor a truly natural fibre.

There are two varieties of Rayon; viscose and high wet modulus (HWM). These in turn are produced in a number of types to provide certain specific properties.

Characteristics

• Soft, smooth and comfortable
• Naturally high in lustre
• Highly absorbent
• Durability and shape retention is low, especially when wet
• Low elastic recovery
• Normally weak, but HWM rayon is much stronger, durable and has good appearance retention.

Applications

• Apparel – blouses, dresses, jackets, lingerie, linings, suits, neck ties etc.
• Furnishing items – bedspreads, bed sheets, blankets, window treatments, upholstery etc.
• Industrial uses e.g. medical surgery products, non-woven products, tyre cord etc.
• Other uses – feminine hygiene products, diapers, towels etc.

Acetate

Acetate consists of a cellulose compound identified as acetylated cellulose – a cellulose salt. Hence it possesses different qualities compared to rayon.

Acetate is thermoplastic and can be formed into any shape by application of pressure combined with heat. Acetate fibres have good shape retention.

Characteristics

• Thermoplastic
• Good drapability
• Soft, smooth and resilient
• Wicks and dries quickly
• Lustrous appearance
• Weak, rapidly loses strength when wet, must be dry-cleaned
• Poor abrasion resistance

Applications

• Primarily in apparel – blouses, dresses, jackets, lingerie, linings, suits, neck ties, etc.
• Used in fabrics such as satins, brocades, taffetas, etc.

Tri-acetate

Tri-acetate consists of acetylated cellulose that retains acetic groupings, when it is being produced as triacetate cellulose. It is a thermoplastic fibre and is more resilient than other cellulosic fibres

Characteristics

• Thermoplastic
• Resilient
• Shape retentive and wrinkle resistant
• Shrink resistant
• Easily washable, even at higher temperatures
• Maintains creases and pleats well

Applications

• Primarily apparel
• Used in clothing where crease / pleat retention is important e.g. skirts and dresses
• Can be used with polyester to create shiny apparel

2.2. Man-made – Non-cellulosic

Polymer Fibres

This group of fibres is distinguished by being synthesised or created from various elements into larger molecules that are called linear polymers.

The molecules of each particular compound are arranged in parallel lines in the fibre. This arrangement of molecules is called molecular orientation.

The properties of such fibres are dependent on their chemical composition and kinds of molecular orientation.

Nylon

In nylon, the fibre forming substance is a long-chain synthetic polyamide in which less than 85% of the amide linkages are attached directly to two aromatic rings. The elements carbon, oxygen, nitrogen and hydrogen are combined by chemical processes into compounds which react to form long-chain molecules, chemically known as polyamides and are then formed into fibres. There are several forms of nylon. Each depends upon the chemical synthesis.

They are: Nylon 4; 6; 6.6; 6.10; 6.12; 8; 10; and 11.

Characteristics

• Highly resilient
• High elongation and elasticity
• Very strong and durable
• Excellent abrasion resistance
• Thermoplastic
• Has the ability to be very lustrous, semi-lustrous or dull
• Resistant to insects, fungi, mildew and rot

Applications

• Apparel – pantyhose, stockings, leggings, etc.
• Home furnishing
• Industrial applications – parachutes, tyre cords, ropes, airbags, hoses, etc.

Polyester

In polyester, the fibre forming substance is any long-chain synthetic polymer composed of at least 85% by weight of an ester of a substituted aromatic carboxylic acid, but not restricted to substituted terapthalate units and para-substituted hydroxybenzoate units.

In producing such fibres, the basic elements of carbon, oxygen and hydrogen are polymerised. Variations are possible in the methods of production, in the combination of ingredients and in the ultimate molecular structures of the fibre forming substance.

Characteristics

• Thermoplastic
• Good strength
• Hydrophobic (non absorbent)

Applications

• Apparel – woven and knits, shirts, pants, jackets, hats etc.
• Home furnishing – bed sheets, blankets, upholstered furniture, cushioning material
• Industrial uses – conveyor belts, safety belts, tyre reinforcement

Spandex

The fibre forming substance used to produce spandex is any long-chain synthetic polymer composed of at least 85% of segmented polyurethane. Variations are possible when producing this fibre.

The basic elements of nitrogen, hydrogen, carbon and oxygen are synthesised with other substances to ethyl ester compounds in polymer chains of soft segments or sections that provide stretch and harder segments that hold the chain together.

Trademarks of three spandex fibres are Cleer-span, Glospan and Lycra.

Characteristics

• Highly elastic
• Comfortable
• High shape retention
• Durable

Applications

• Never used alone, but always blended with other fibres
• Apparel and clothing items with stretch for comfort and fit
• Hosiery
• Foundation garments
• Swimwear, athletic, aerobic apparel
• Lingerie, leggings and socks
• Shaped garments e.g. bra cups
• Gloves

Acrylic

In acrylics, the fibre forming substance is any long chain polymer composed of at least 85% by weight of acrylonitrile units. Using complicated processes, carbon, hydrogen and nitrogen, the basic elements are synthesised with small amounts of other chemicals into larger polymer combinations. Variations are possible in the methods of production, in the combination of ingredients and in the ultimate molecular structures of the fibre forming substance.

Characteristics

• Soft, warm handling characteristics similar to wool
• Resilient
• Shape retentive

Applications

• Apparel
• Home furnishing

3. Man-made – Protein Fibres

The protein from such products as corn and milk has been processed chemically and converted into fibre. However, such fibres are not commercially successful.

4. Man-made – Rubber Fibres

The fibre forming substance is comprised of natural and synthetic rubber. The treated rubber is produced in strands, so that the cross-section is either round or square and the longitudinal surface is relatively smooth.

5. Man-made – Metallic Fibres

These fibres are composed of metal, plastic-coated metal, metal-coated plastic, or a core completely covered by metal. These fibres are usually produced in flat, narrow, smooth strips which possess high lustre.

Applications

• Decorative yarns in apparel and home furnishing items.

6. Man-made – Mineral Fibres

Various minerals have been manufactured into glass, ceramic and graphite fibres having prescribed properties for specific uses.

Glass

Although glass is a hard and inflexible material, it can be made into a fine, translucent textile fibre that has an appearance and feel of silk.

Natural minerals such as silica sand, limestone, soda ash, borax, boric acid, feldspar and fluorspar have been fused under very high temperatures into glass which is processed into a fibre.

Characteristics

• Inert
• Highly flame resistant

Applications

• Heat resistant industrial applications

Textile Fibre Parameters

Fibrous materials should possess certain properties to become a suitable textile raw material. Properties which are essential for acceptance as a suitable raw material may be classified as ‘primary properties’. The other properties which add specific desirable character or aesthetics to the end product and its use may be classified as ‘secondary properties’.

Primary Properties

1. Length
2. Tenacity (strength)
3. Flexibility
4. Cohesion
5. Uniformity of properties

Secondary Properties

1. Physical shape
2. Specific gravity (influence weight, cover etc.)
3. Moisture regain and absorption (comfort, static electricity etc.)
4. Elastic character
5. Thermo plasticity (softening point and heat – set character)
6. Dyeability
7. Resistance to solvents, corrosive chemicals, micro-organisms and environmental conditions
8. Flammability
9. Lustre

Physical Properties

Cotton

Linen

Wool

Silk

Rayon

Acetate

Nylon

Polyester

Acrylic

Fibre Properties – Comparison

Absorbency

*Moisture regain is expressed as a percentage of the moisture-free weight at 70º Fahrenheit and 65% relative humidity.

Thermal properties

Effects of Acids

Effects of Alkalis

Effects of Organic Solvents

Effects of Sunlight

Cleanliness and Washability

Effects of Perspiration

*Perspiration can be acidic or alkaline, depending on the individual’s metabolism.

Effects of Mildew

Effect of Heat

Effects of Insects