Class 8 Science


Plastic too is a polymer. But arrangement of units is different in different types of plastic. In some plastics, the individual units are linked in a linear fashion. In some other plastics, the individual units are cross-linked.

Types of Plastic


Some plastics easily get deformed on heating, and can be easily bent and reshaped by heating. They are called thermoplastic. Polythene and PVC are examples of thermoplastic. Thermoplastic is used for making combs, toys, buckets, mugs, etc.

Thermosetting Plastic

Some plastics do not get deformed on heating, and cannot be re-molded into a new shape. Such plastics are called thermosetting plastic. Bakelite and melamine are examples of thermosetting plastic. Bakelite is used for making electrical switches and switchboards because it is a poor conductor of heat and electricity. Melamine is resistant to fire and is hence used for making utensils.

Reasons for popularity of plastic:

Plastic and the Environment

Biodegradable: A material which can be decomposed by microbes is called a biodegradable material, e.g. jute, cotton, paper, leftover food, etc.

Non-biodegradable: A material which cannot be decomposed by microbes is called a non-biodegradable material, e.g. plastic, iron, copper, etc.

The non-biodegradable nature of plastic poses a big problem. Plastic has become very popular due to many of its inherent benefits. But popularity of plastic is proving to be a curse for the environment. Plastic waste is getting accumulated all around us, in the street, on sidewalk, in drains, on garbage dumping sites, etc. This is creating a burden of plastic waste on the earth.

Harms of plastic bags:

How to tackle the problem of plastic waste?