CBSE Class 8 Science Chapter 3 Notes: Synthetic Fibres And Plastics
Clothes that we wear on a daily basis are made of fabrics. Fabrics are made of fibres which are obtained from natural and artificial sources. Wool, silk, and cotton are a few examples of natural fibres and fibres like polyesters and terylene are a few examples of synthetic fibres. In class 8 science chapter 3, the various types of synthetic fibres along with their characteristics are mentioned.
Types of Synthetic Fibres
Natural fibres are obtained by animals and plants while synthetic fibres are obtained by chemical processing of petrochemicals. Depending on the type of chemicals used for the manufacture of synthetic fibres, they are classified as follows:
The different types fibres differ from each other in their water absorbing capacity, strength, durability, nature of burning, cost and water absorbing capacity.
A synthetic fibre is made of many small units joined together to form a large unit is known as a polymer. Hence, we can conclude that all polymers are synthetic fibres. Plastics is also a polymer like synthetic fibres. Today, it is impossible to imagine a life without plastics. A following are a few properties of plastics that make it a material of choice over others for various things like storing food and more:
- Plastics are non-reactive and they do not corrode easily
- Plastics are strong, light and durable
- Plastics are poor conductors of heat and electricity
A plastic that can be deformed and bent easily on heating is known as a thermoplastic. A plastic which when moulded once cannot be softened by heating is known as a thermosetting plastic.
Plastics are non-biodegradable and release poisonous fumes into the atmosphere resulting in air pollution. We need to use plastics and synthetic fibres judiciously in such a manner that we can both enjoy their good qualities and at the same time minimise its environmental hazards for the living communities.
Synthetic Fibres And Plastics Class 8 Extra Questions
- Why are a few fibres called synthetic?
- Why are plastic containers favoured for storing food?
- Explain the difference between thermoplastic and thermosetting plastics.
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