Description of plastic

Plastic 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:
Thermoplastic: 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.