Synthetic Fibres and Plastics: NCERT Class 8 Chemistry

Synthetic Fibres and Plastics: Synthetic fibres and plastics are commonly used in our daily lives. The clothes we wear, the curtains, the sweaters, ropes and nets are all examples of fibres. However, the Fibre used to make clothes is way different from the fibres used to make ropes and nets. Let’s learn the difference between these two types of fibres and their uses in our day to day life. 

Study Everything About Fibres Here

Fibres

We know that fibres are long thin thread-like structures used to make various objects ranging from clothes to nets and ropes. However, their usage depends on the sources from where they are derived. Basically, fibres are divided into two categories. These are-

i) Fibres from Natural Sources or Natural Fibres

The fibres obtained from nature, i.e., animals or plants, are known as natural fibres. e.g. cotton, wool, linen, silk, etc. Fibres obtained from plant sources are called cellulosic Fibre, e.g., cotton and linen. The fibres from animal sources are also known as protein fibres, e.g., wool and silk. 

ii) Man-Made fibres or Synthetic Fibres

The fibres made in laboratories using chemicals or various petrochemical products are known as synthetic fibres. Acrylic, polyester and Nylon are all synthetic fibres.

Natural and Synthetic Fibres: Differences

Synthetic Fibre is composed of chains of small units called monomers that combine to form polymers.

Polymer is a Greek word in which ‘poly’ means ‘many’ and ‘mer’ means units. Hence, polymers are large molecules made up of several monomers linked together through the process of polymerisation. For example – ‘Cotton’ is a polymer called ‘Cellulose’. It comprises a large number of single repeating units (or monomers) called ‘Glucose’. All synthetic fibres are also examples of polymers.

Synthetic Fibres: Types

The types of synthetic fibres are explained below:

Rayon

We know that silk fibre obtained from silkworms is expensive and has a beautiful texture, look and feel. Hence, attempts were made to make silk artificially, which led to the invention of artificial silk known as Rayon. It is made by treating wood pulp chemically.

Rayon is a versatile fibre. It is also known as Artificial silk because it resembles silk in appearance, texture and shine. It can imitate the texture and feel of cotton, silk, wool, and linen with drape and slipperiness akin to Nylon.

Although Rayon is obtained from a natural source, wood pulp, yet it is an artificial fibre.

Rayon: Characteristics

(i) It is cheaper than silk and can be woven into silk-like fibres.
(ii) Rayon is highly absorbent, comfortable and soft. 
(iii) It can be draped well and can be easily dyed in a wide range of colours.

Rayon: Uses

(i) Rayon is widely used in all types of clothing and home furnishings.
(ii) It is mixed with cotton to make curtains, bedsheets, and bedspreads.
(iii) It is mixed with wool to make blankets and carpets.
(iv) It is used to make tyre cords for automobiles. 

Nylon

Nylon is another synthetic fibre prepared without using any natural raw materials (materials produced by plants and animals). It is the first synthetic Fibre made from coal, water and air.

Nylon: Characteristics

1. Nylon is a lightweight, weather-resistant and robust Fibre.
2. It is elastic and does not absorb much water.
3. It is easy to wash and dries quickly.
4. Nylon is stronger than steel wire. 

Nylon: Uses

1. It is used in making ropes for rock climbing, fishing nets and tents.
2. Nylon is used in making socks, toothbrushes and seat belts.
3. It is used in making parachutes because of its high tensile strength. 

Polyester

Polyester is a synthetic fibre made up of repeating units of a chemical called an ester (Poly + ester). Ester is a fruity smelling organic compound. It is derived from coal, air, water and petroleum. Polyester does not get wrinkled easily. Hence, a fabric made from this Fibre is easy to wash and does not need to be ironed, making it suitable for dress material.

Polyester: Characteristics

1. The fabrics made out of this Fibre does not get wrinkled easily.
2. It remains crisp and doesn’t need ironing. 
3. Polyester is easy to wash, does not absorb water, and dries quickly.

Some Popular Polyester Fibres are

1. Terylene (often known by the brand name Dacron) is a popular polyester that can be drawn into very fine Fibre and can be woven like any other yarn.
2. Polyethylene terephthalate (P.E.T.) is used for making bottles, wires, utensils and films.

Polyester is often used in blended fibres. These fibres are formed by mixing natural and synthetic fibres. For Example – Polywool (polyester + wool), Polycot (polyester + cotton), Terrycot (Terylene + Cotton).

Polyester: Uses

1. Polyester is used to make various textiles (including curtains, sarees, dress materials, etc.).
2. It can be easily blended with natural fibres (like cotton and wool).
3. It is used in making magnetic recording tapes, films etc. (as Mylar).
4. Polyester is used to make water hoses and sailboats for firefighting purposes.

Acrylic

Acrylic ‘containing acryl (or acrolein) is a synthetic fibre that resembles wool. Natural wool is quite expensive, whereas clothes made from acrylic is cheaper and affordable. 

Acrylic: Characteristics

1. Acrylic fibres are strong, lightweight and warm.
2. It can be dyed easily and is more durable and affordable than natural wool.
3. It is wrinkle-resistant and cheaper than wool.
4. It is resistant to the action of moths and insects and can be stored easily.

Acrylic Fibre: Uses

1. Acrylic is used to make woollen clothes like sweaters, scarves, tracksuits.
2. It is used as linings for boots and gloves.
3. Acrylic is used in home furnishings such as furniture, carpets, blankets and upholstery fabrics.
4. It is used to make fake fur for making toys and fur accessories.
5. It is hypoallergic and can be used to make garments for babies (as the fabric is machine-washable).

Synthetic Fibres: Characteristics

The characteristics of synthetic fibres are explained below:

Plastics

Plastic is also a polymer like synthetic Fibre. Not all plastics have the same arrangement of monomer units. In some, it is linear, whereas in others, it is cross-linked. 

Plastics: Characteristics

1. Plastics are easily mouldable and are found in all possible shapes and sizes. 
2. It can be recycled, reused, coloured, rolled into sheets or made into wires. 
3. It is lightweight and resistant to corrosion.
4. Plastics are strong, lightweight and can be easily handled.
5. These are poor conductors of heat and electricity.

Plastics: Types

1. Thermoplastics: Certain plastics that can be bent or deformed easily on heating are known as thermoplastics. Examples are PVC (Poly Vinyl Chloride) and Polythene. 

Thermoplastics have a linear arrangement of monomers and are used in making toys, bottles, combs, containers, etc. 

2. Thermosetting plastics: Such plastics which when moulded once, cannot be softened or deformed by heating, are called thermosetting plastics. Examples are Bakelite and Melamine. 

Thermosetting plastics have a cross-linked arrangement of monomers.

Bakelite is a poor conductor of electricity and heat and thus is used for electrical switches, handles of various utensils and other electrical appliances. 

Melamine is a versatile material and a poor conductor of heat. It is excellent fire-resistant and thus used to make floor tiles, kitchenware, fabrics that resist fire.

Plastics: Uses

1. Plastic (Bakelite) is used in making electrical appliances and protects individuals from any electrical shocks.
2. Melamine (thermosetting plastic) is used to make crockeries and tolerates heat more than any other form of plastic. It can hold hot liquids or dishes served in it.
3. Plastics are widely used in cars, aircraft and spacecraft.
4. These are resistant to the action of chemicals. Hence, they are suitable for storing chemicals.
5. It is used to make carry bags(Polythene) and non-stick covers on cookware (Teflon).
6. It is used as packaging for food and non-food items.
7. Used in the healthcare industry for packaging of tablets, syringes, doctor’s gloves, a number of medical instruments, and threads for stitching wounds.
8. Used to make cookware used in microwave ovens.
9. Used to make the fire-resistant uniform for firefighters (made of Melamine)

Plastics and the Environment

Biodegradeable substances such as vegetable waste get easily decomposed through natural processes, but plastic, a non-biodegradable substance, takes several years to decompose. Therefore, it poses a serious threat to the environment. It is a major contributor to pollution, be it land, air or water. Plastic is not eco friendly because it takes several years to degrade. It has a negative impact on the environment. Furthermore, the synthetic material’s burning process is quite slow, and it does not simply burn fully. It pollutes the air by releasing a large amount of harmful gases into the atmosphere.

5 R’s to Minimise the Environmental Damage caused by Plastic

1. Refuse: We should buy only those things that we need.
2. Reduce: The use of plastics in our everyday lives should be avoided.
3. Reuse: Certain items can be reused instead of throwing them away.
4. Recover: Altering or changing used items to be used in a different way.
5. Recycle: Plastic waste can be sorted and reprocessed into functional and useful products. This, in turn, reduces our carbon footprint.

How to Reduce the Use of Plastic?

1. We should avoid the use of plastics things as far as possible.
2. The biodegradable and non-biodegradable wastes should be collected and disposed of separately.
3. We should not throw plastic bags or other plastic articles into water bodies, drains or on roads.
4. We should always carry cotton or jute bags for shopping.
5. We should always buy products with less plastic packaging. 
6. Recycling and reuse of plastics should be encouraged.

Important Questions on Synthetic Fibres and Plastics

The Synthetic fibres and plastics important questions are explained below:

Q.1. Why is melamine used for making kitchenware?
Ans: Melamine is a thermosetting plastic, hence does not melt on being heated. It resists heat better than any other plastics. Therefore, it is used for making kitchenwares.

Q.2. Why is it advised not to wear synthetic clothes while working in a laboratory or working with fire in the kitchen?
Ans: When heated, the synthetic fibres melt. With synthetic fibres, this is actually a negative. It can be highly dangerous if the material catches fire. The fabric melts and adheres to the person who is wearing it. As a result, synthetic clothing should not be worn in a laboratory or when working with fire in the kitchen.

Q.3. Is using plastics for storing food safe?
Ans: Though it is more efficient to store and transport food in a plastic container. Chemicals used in the manufacture of plastics, on the other hand, seep into the food and contaminate it. Despite the fact that it is used in such a small amount, it exposes our bodies to hazardous and deadly compounds.

Summary

Synthetic fibres and plastics are involved in our daily lives to the core. We are greatly indebted to the versatile nature of synthetic fibres and plastics. As they are immensely needed in our daily lives, it’s high time that we become fibre-wise. We need to develop habits that are environmentally friendly. 

Through this article, we learnt the uses and variety of synthetic fibres available. We also learnt the types of plastics and how one is better than the other. This article also listed some of the ways through which we can become responsible citizens and contribute our efforts in making this world a better place to live in. 

Study About Plant Fibres Here

Frequently Asked Questions on Synthetic Fibres and Plastics

Frequently asked questions related to synthetic fibres and plastics are listed as follows:

Q.1. What is the difference between synthetic Fibre and plastic?
Ans: Materials used to make synthetic fibres can be used to make plastics; however, all materials that are used in making plastics cannot be used to make synthetic fibres. Most fibres are made from compounds that form long polymer strands, e.g., Nylon and Dacron. Plastic is generally a synthetic polymer that can be melt processed.

Q.2. How are synthetic fibres and plastics made?
Ans: Synthetic Fibre is made by linking multiple units of a chemical substance called a monomer. These units in Fibre are joined together like a chain. Almost all synthetic fibres are made by using raw materials from petroleum known as petrochemicals.
Natural, organic resources such as cellulose, coal, natural gas, salt, and, of course, crude oil are used to make plastics. Plastics are made using two basic processes: polymerisation and polycondensation, both of which require specialised catalysts.

Q.3. Are synthetic fibres plastic?
Ans: Synthetic fibres are polymers in which the monomers are linked to form long chains. In contrast, plastic is also a polymer but is not similar to synthetic fibres—the properties and characteristics of synthetic Fibre are not similar to that of plastics. For example – plastic containers used to store food has properties different from that nylon ropes used for rock climbing. 

Q.4. Which is the strongest synthetic Fibre?
Ans: Nylon is the strongest synthetic Fibre.

Q.5. What is synthetic Fibre? Give an example?
Ans: The fibres that are made in laboratories using chemicals or various petrochemical products are known as synthetic fibres. Acrylic, polyester and Nylon are all synthetic fibres.

We hope this detailed article on synthetic fibres and plastics is helpful to you. If you have any queries on this page or in general about synthetic fibres, reach us through the comment box below and we will get back to you as soon as possible.