ROLE OF PLASTICS IN EVERYDAY LIFE
You must be familiar with many plastic articles used everyday. Make a list of such items and their uses.
Figure 3.6: (a) Linear (b) Cross-linked arrangements
Plastic is also a polymer like synthetic fibre. All plastics do not have the same type of arrangement of units. In some, it is linear, whereas in others it is cross-linked. (Fig. 3.6).
Plastic articles are available in all possible shapes and sizes as you can see in Fig. 3.7. Have you ever wondered how this is possible? The fact is that plastic is easily mouldable i.e. can be shaped in any form. Plastic can be recycled, reused, coloured, melted, rolled into sheets or made into wires. That is why it finds such a variety of uses.
Figure 3.7: Various articles made of plastics
Polythene (Poly+ethene) is an example of plastic. It is used for making commonly used polythene bags. Now, try to bend a piece of plastic yourself. Can all the plastic articles be bent easily? You will observe that some plastic articles can bend easily while some break when forced to bend. When we add hot water to a plastic bottle, it gets deformed.
Source: This topic is taken from NCERT TEXTBOOK
THERMOPLASTICS AND THERMOSETTING PLASTICS
Thermoplastics
Plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics. Polythene and PVC are some of the examples of thermoplastics. These are used for manufacturing toys, combs, and various types of containers.
Figure 3.8(a): Articles made of thermoplastics
Thermosetting plastics
There are some plastics which when moulded once, can not be softened by heating. These are called thermosetting plastics. Two examples are bakelite and melamine. Bakelite is a poor conductor of heat and electricity. It is used for making electrical switches, handles of various utensils, etc. Melamine is a versatile material. It resists fire and can tolerate heat better than other plastics. It is used for making floor tiles, kitchenware and fabrics which resist fire.
Figure 3.8(b): Articles made of thermosetting plastics
Source: This topic is taken from NCERT TEXTBOOK