Fibres are thread-like materials used to make cloth. For thousands of years, humans used only natural fibres obtained from plants and animals — cotton, jute and coir from plants, and silk and wool from animals. Natural fibres such as cotton, silk and wool are still very popular, but they have some limitations: they are produced slowly, are limited in quantity and are expensive. The need for cheaper, stronger and more versatile clothing materials led scientists to develop synthetic fibres, which are made by human beings using chemical processes.
Synthetic fibres are manufactured from chemical substances called polymers. A polymer is a chain of many small repeating units called monomers joined together. For example, the synthetic fibre rayon is made from the polymer of cellulose, and nylon is made from amide monomers. Synthetic fibres and plastics are a part of our everyday life — in our clothes, ropes, tyres, bags, bottles and toys. In this chapter we study the types of synthetic fibres, their properties, and the properties and uses of plastics, along with their environmental impact.
2. Synthetic Fibres and Their Types
Synthetic fibres are made in factories using chemical processes and are also called man-made fibres. The important synthetic fibres are:
Rayon: Rayon is made from the natural polymer cellulose obtained from wood pulp. Because it is made from a natural source (wood), rayon is called a regenerated fibre and is often called artificial silk. It is cheaper than silk, has a silky lustre and absorbs moisture well, so it is used to make clothes, curtains, bedsheets and tyre cords.
Nylon: Nylon is the first fully synthetic fibre made without any natural raw material. It was prepared in 1931 for the first time from coal, water and air. Nylon is extremely strong, elastic and lightweight, and it resists wear and tear. It is used for making socks, ropes, parachutes, tents, toothbrush bristles and fishing nets.
Polyester: Polyester is made from chemical substances obtained from petroleum. It does not absorb much water, dries quickly, keeps its shape and resists wrinkling, so it is ideal for dress materials and sarees. Common polyester varieties include terylene and tericot (a blend of polyester and cotton).
Acrylic: Acrylic is a synthetic fibre that resembles wool and is therefore called artificial wool. It is cheaper than natural wool, soft, lightweight, warm and quick to dry. It is used to make sweaters, shawls, blankets and winter clothing.
PVC and other special fibres: Polyvinyl chloride (PVC) is used to make raincoats and bags, while some fibres are made fire-resistant for special protective clothing.
3. Characteristics of Synthetic Fibres
Synthetic fibres have several characteristic properties that make them different from natural fibres:
Strength and durability: Synthetic fibres like nylon are very strong, even stronger than steel wires of the same weight.
Low absorbency: Most synthetic fibres absorb very little water, so clothes made of them dry quickly. However, this also makes them uncomfortable in hot and humid weather because they do not absorb sweat.
Elasticity and quick shape recovery: Synthetic fibres are elastic and easily regain their shape after stretching, so clothes do not shrink or lose shape easily.
Resistance to insects, moths and mildew: Unlike wool, synthetic fibres are not attacked by moths or insects.
Heat sensitivity: Synthetic fibres are poor conductors of heat and can melt on heating. Therefore, they should never be ironed with a very hot iron, and one should be careful around fire while wearing synthetic clothes.
A great advantage of synthetic fibres is that they are lightweight, strong and easy to dye in many colours, which is why they are used in everything from casual wear to safety ropes.
4. What Are Plastics?
Like synthetic fibres, plastics are also polymers, made of very large molecules formed by joining many small monomer units. Plastics can be moulded into any shape and harden on cooling, which is why their name comes from the Greek word plastikos meaning "able to be moulded". Plastics are light, strong, durable, cheap and poor conductors of heat and electricity.
Plastics are of two main types:
Thermoplastics: These soften on heating and can be moulded again and again. They can be reshaped and recycled. Examples: polythene, PVC and polystyrene. Thermoplastics are used for making buckets, mugs, toys and pipes.
Thermosetting plastics: These cannot be softened by heating once they are moulded and set. If heated again, they burn rather than melt. Examples: bakelite and melamine. Because of their heat resistance, bakelite is used to make electrical switches and handles of utensils, and melamine is used for making kitchenware and floor tiles.
5. Uses of Plastics
Plastics are used in almost every part of life because of their useful properties:
Bakelite: Being a poor conductor of electricity and heat, it is used for electrical switches, plugs and handles of cooking utensils.
Melamine: It resists heat and does not get damaged by mild chemicals, so it is used for making floor tiles, kitchenware, utensils and fire-resistant fabrics.
Polythene and PVC: Used for making carry bags, pipes, raincoats, and insulation on electric wires.
Plastics in healthcare: Disposable syringes, blood bags, artificial heart valves and prostheses are made from special plastics because they are safe, disposable and do not react with body fluids.
Plastics in daily use: Toys, furniture, combs, buckets, television and mobile covers, bottle caps and packaging materials are all made of plastic.
The property of plastics being poor conductors of heat makes them ideal for insulating handles of frying pans and other cooking vessels.
6. Plastics and the Environment
The very properties that make plastics useful — being durable and non-biodegradable — also make them a serious environmental problem. Plastics do not get decomposed by microorganisms; substances that cannot be broken down by living organisms are called non-biodegradable substances. Plastic waste accumulates in the environment for hundreds of years.
Plastics thrown in garbage pollute soil and water.
When burned, plastics release harmful gases and toxic chemicals that pollute the air.
Animals sometimes swallow plastic and die.
Discarded plastic bags clog drains and cause waterlogging.
Burning PVC releases dangerous gases that can harm human health.
Because plastic is so harmful to the environment, the 3 R's — Reduce, Reuse and Recycle — must be practised. We should reduce our use of plastic, reuse plastic articles where possible, and recycle plastic instead of throwing it away. Government rules discourage the use of thin polythene carry bags and encourage cloth and jute bags.
7. Biodegradable and Non-biodegradable Materials
Materials can be divided into two groups on the basis of their ability to decompose:
Biodegradable substances: Materials that are broken down into simple substances by microorganisms (decomposers). Examples: food waste, paper, cotton cloth, jute bags and wood. These return to the soil naturally.
Non-biodegradable substances: Materials that cannot be broken down by microorganisms into harmless substances. Examples: plastics, polythene bags and synthetic fibres. These remain in the environment for a very long time and cause pollution.
This distinction is the basis of the environmental problems caused by plastics and the reason why the 3 R's are essential.
Quick Revision Tables
Table 1: Synthetic Fibres and Their Uses
Fibre
Raw Material / Source
Key Property
Uses
Rayon
Cellulose from wood pulp (regenerated)
Silky lustre, absorbs moisture
Artificial silk, curtains, bedsheets, tyre cords
Nylon
First fully synthetic, from coal, water and air
Very strong, elastic, lightweight
Socks, ropes, parachutes, toothbrush bristles
Polyester
Petroleum products
Low absorbency, wrinkle resistant
Dress materials, sarees, terylene, tericot
Acrylic
Synthetic polymer
Resembles wool, soft, warm
Sweaters, shawls, blankets (artificial wool)
Table 2: Thermoplastics vs Thermosetting Plastics
Feature
Thermoplastics
Thermosetting Plastics
Effect of heat
Soften and can be remoulded on heating
Cannot be remoulded; burn on strong heating
Recyclability
Can be recycled/reshaped
Cannot be reshaped once set
Examples
Polythene, PVC, polystyrene
Bakelite, melamine
Uses
Buckets, toys, pipes, mugs
Electrical switches, handles, kitchenware
Table 3: Biodegradable vs Non-biodegradable
Feature
Biodegradable
Non-biodegradable
Breakdown by microorganisms
Yes
No
Examples
Paper, cotton, jute, food waste
Plastics, polythene, nylon
Effect on environment
Return to soil harmlessly
Accumulate and cause pollution
Mind Map
graph TD
A["Synthetic Fibres and Plastics"] --> B["Synthetic Fibres"]
B --> B1["Rayon: artificial silk"]
B --> B2["Nylon: strong, parachutes"]
B --> B3["Polyester: terylene"]
B --> B4["Acrylic: artificial wool"]
A --> C["Plastics"]
C --> C1["Thermoplastics: remouldable, PVC"]
C --> C2["Thermosetting: bakelite, melamine"]
A --> D["Properties"]
D --> D1["Light, strong, durable"]
D --> D2["Poor conductors of heat and electricity"]
D --> D3["Non-biodegradable"]
A --> E["Environmental Impact"]
E --> E1["Pollution of soil, water, air"]
E --> E2["3 R's: Reduce, Reuse, Recycle"]
Important Diagrams (SVG)
Diagram 1: Polymer Structure and Fibre Types
Diagram 2: 3 R's for Plastic Waste Management
Common Mistakes
Thinking rayon is fully synthetic: Rayon is made from cellulose (wood pulp), a natural polymer, so it is a regenerated fibre, not fully synthetic. Nylon was the first fully synthetic fibre.
Calling acrylic artificial silk: Acrylic resembles wool, so it is artificial wool. Rayon resembles silk and is called artificial silk.
Confusing thermoplastics and thermosetting plastics: Thermoplastics (polythene, PVC) soften and can be remoulded on heating; thermosetting plastics (bakelite, melamine) cannot be remoulded.
Believing plastics are biodegradable: Plastics are non-biodegradable and are not broken down by microorganisms, which is why they pollute the environment.
Stating all plastics conduct electricity: Plastics are poor conductors of heat and electricity, which is exactly why bakelite is used in electrical switches.
Forgetting nylon's date: Nylon was first prepared in 1931 from coal, water and air — a favourite factual question.
Ironing synthetic clothes very hot: Synthetic fibres melt on heating, so they must be ironed at low temperature; students often miss this safety point.
Exam Tips
Learn one example-use pair for each fibre: Rayon–curtains, Nylon–parachutes, Polyester–terylene sarees, Acrylic–sweaters.
Differentiate thermoplastics vs thermosetting with examples: polythene/PVC vs bakelite/melamine is a guaranteed question.
Always state the reason for using bakelite in switches — because it is a poor conductor of electricity and heat.
Define polymer and monomer first: Many questions ask "what is a polymer?" — remember chain of monomers.
Mention the 3 R's in any question about plastic and the environment: Reduce, Reuse, Recycle.
Remember the danger of burning plastic: it releases harmful gases — important for environmental questions.
Conclusion
Synthetic fibres and plastics are man-made polymers that have revolutionised clothing, industry and daily life. Rayon, nylon, polyester and acrylic each bring valuable properties — strength, elasticity, comfort, warmth or quick drying — while thermoplastics and thermosetting plastics provide mouldable, durable and heat-resistant materials for countless uses. However, the durability that makes plastics so useful also makes them non-biodegradable, creating serious environmental pollution. The solution lies in our own habits: reduce, reuse and recycle plastic, and choose biodegradable alternatives like cotton and jute wherever possible. Understanding both the benefits and the costs of these materials helps us use them wisely and keep our environment clean.