What is Animal Fibre Definition Types Examples and Formation Process
Animal fibres are naturally occurring fibres that are sourced from animals, as the name suggests. Animal fibres are made up of different types of proteins in general. Some of the most common animal fibres are wool and silk. You must know that all animal fibres are extracted from different animals and hence have different properties from one another. Also, the kind of fibres depends from one animal to another.
Consider, for example, both Merino and Cotswold are two different kinds of wool that are extracted from different species of sheep. Merino is known for its softer texture, whereas Cotswold is known for its coarse texture. You must also know that the natural fibres from animals tend to vary in consistency than the synthetic fibres. The synthetic ones are more uniform. We will learn today about what animal fibres are, the difference between animal fibres and plant fibres, and the different types of animal fibres.
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Names of Animal Fibres
The fibres obtained from animals are generally textile. These fibres are generally produced from the animal’s fur, skin, hair, or even secretion in the case of the silkworm. Once these animal fibres are extracted they are generally knitted or woven for forming beautiful animal fabrics. If you have to name two fibres obtained from animals, they can be silk and wool.
However, if you consider historically, these animal fibres have been employed for manufacturing warm and soft jackets, shawls, blazers, coats, ponchos, and several other forms of clothes and accessories. If you have to name any two animal fibres applications that are rougher, they are usually covers, carpets and rugs.
Difference Between Animal Fibres and Plant Fibres
Types of Animal Fibres
If we have to name two animal fibres that are widely used, they are wool and silk. Let us now learn about the types of animal fibres in detail.
Wool
Wool is an animal fibre derived from different animal furs which belong to the Caprinae family. We usually relate wool to sheep, however, wool can also be derived from other animals like goats, rabbits, and alpacas. Different kinds of wool from different animals have different properties from one another. The main difference between the wool and hair of sheep is that the wool of the sheep consists of scales which overlap in the same manner as the shingles on a roof. Many kinds of wools are also known to possess more than 20 kinds of such bends in just one inch. However, the diameter of one strand of the wool ranges from 17micrometres to about 35 micrometres.
Let us discuss about the feature of those different types of wool fibres -
Angora wool, the rabbit hairs obtained from a special species of rabbits named as Angora rabbit. The fur of the angora rabbits are considered to be extremely soft and pleasant to touch, thus due to its desirable characteristics are in a very high demand. It is often mixed with other types of wool to add warmth and softness in the final product.
Alpaca fibre: this is obtained from one of the South American camelid mammal species, by the same name Alpaca. This wool is very light in comparison to the normal sheep fibre and not only that, it is warmer than the traditional sheep wool.
Wool obtained from the american bison, known as the bison wool, is also quite famous in the textile industry.
One extremely famous type of wool goes by the name of Cashmere wool (derived from the word Kashmiri), and is processed from the fur of the Cashmere goat found in the Kashmir territory of India. This type of wool has a luxurious texture in it and is extremely soft and lightweight. Kashmir shawl (also spelled as Cashmere) created from the Cashmere wool is quite popular in the textile industries around the world.
Like rabbits, goats also have pieces with the name of angora goats, the fur of which is called the Mohair wool, this type of wool is considered very similar to silk. Mohair is famously known for its durability.
Silk
Silk is regarded as a naturally occurring protein fibre. It can also be woven into textiles in different ways. The most commonly known silk form is the which is obtained from the larvae of Bombyx mori species. Silk rearing is called sericulture. The degummed fibres which are obtained from Bombyx mori have a diameter which ranges from 5 - 10 m. There are different types of silk which are famous for their shiny appearance. This is because of the triangular prism-like and cross-sectional structure of these fibres. These prism-like fibrous structures tend to allow light which is incident to the silk fibres to refract at varying angles.
You must know that one whole silkworm cocoon produces one long fibre. Therefore, one should be careful while unwinding these fibres from the silkworm cocoons. Also, the quality of the silk fibres depends on how healthy the silkworm is. This, in turn, depends on the living conditions and the food which they are provided with.
Spider silk is amongst the most powerful naturally occurring fibres known to man. It is the strongest dragline silk which is believed to be about three times stronger than kevlar and more than five times tougher than steel. There are some types of spider silks that are known for their enhanced elasticity. The silk which is woven by the ogre-faced spider is considered to be stretchable more than five times its length without damaging itself!
FAQs on Animal Fibre in Chemistry Structure Properties and Uses
1. What is animal fibre in chemistry?
Animal fibre is a natural protein fibre obtained from the hair, fur, or secretions of animals. In chemistry, animal fibres are composed mainly of the protein keratin (in wool and hair) or fibroin (in silk).
- They are classified as protein polymers.
- They contain elements such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sometimes sulfur (S).
- Examples include wool and silk.
2. What are the main types of animal fibres?
The main types of animal fibres are wool and silk. These are natural protein fibres obtained from different animal sources.
- Wool: Obtained from the fleece (hair) of sheep, goats, and other animals; composed mainly of keratin.
- Silk: Obtained from the cocoon of the silkworm; composed mainly of fibroin.
3. What is wool made of chemically?
Wool is chemically made of the protein keratin, which is a natural polymer of amino acids. Keratin consists of long chains of amino acids linked by peptide bonds (–CO–NH–).
- Contains elements: C, H, O, N, and S.
- Sulfur comes from the amino acid cysteine, forming disulfide (–S–S–) bonds.
- Disulfide bonds give wool its strength and elasticity.
4. What is silk made of chemically?
Silk is chemically made of the protein fibroin, a natural polymer composed of amino acids. Fibroin contains repeated sequences of amino acids such as glycine and alanine linked by peptide bonds.
- Contains C, H, O, and N.
- Has a highly ordered structure, giving silk its smooth texture and strength.
- Produced by silkworms during cocoon formation.
5. How are animal fibres different from plant fibres?
Animal fibres are protein-based polymers, whereas plant fibres are carbohydrate-based polymers mainly composed of cellulose. The key chemical differences are:
- Animal fibres: Made of proteins (keratin or fibroin); contain nitrogen and sometimes sulfur.
- Plant fibres: Made of cellulose, a polymer of glucose with repeating unit (C6H10O5)n; do not contain nitrogen.
- Animal fibres burn with the smell of burnt hair, while plant fibres burn like paper.
6. Why are animal fibres classified as natural polymers?
Animal fibres are classified as natural polymers because they are long-chain macromolecules formed naturally from repeating amino acid units. In chemistry:
- Proteins such as keratin and fibroin are polymers of amino acids.
- Amino acids are linked by peptide bonds.
- The polymer chains have high molecular mass and repeating structural units.
7. How do acids and bases affect animal fibres?
Animal fibres are damaged by strong acids and bases because they break the peptide bonds in proteins. Chemically:
- Strong acids can hydrolyze peptide linkages, weakening the fibre.
- Strong bases can also cause protein degradation.
- Mild detergents are preferred for washing wool and silk.
8. What is the chemical test to identify animal fibres?
Animal fibres can be identified by the burning test and the biuret test for proteins. The identification methods include:
- Burning test: Animal fibres burn with the smell of burnt hair due to protein decomposition.
- Biuret test: Gives a violet color in the presence of peptide bonds when treated with alkaline CuSO4(aq).
9. Why do animal fibres shrink on heating?
Animal fibres shrink on heating because heat disrupts hydrogen bonds and alters the protein structure. Specifically:
- Keratin and fibroin have hydrogen bonds stabilizing their structure.
- Heat weakens these intermolecular forces.
- The fibre contracts and may become brittle.
10. What are the chemical properties of animal fibres?
The chemical properties of animal fibres are mainly determined by their protein composition and peptide bonds. Key properties include:
- They are biodegradable natural polymers.
- They react with acids and bases due to peptide linkages.
- They contain nitrogen and sometimes sulfur (in wool).
- They decompose on strong heating rather than melting.
