Plastic

 Plastic is an artificial polymer which can be changed to any shape. The word plastic is driven from greek word “plastiko” which means changeable shape. Raw material to make plastic is obtained from crude mineral oil.

Monomer:  Monomer is  a molecule of any of a class of compounds, mostly organic, that can react with other molecules to form very large molecules, or polymers. The essential feature of a monomer is polyfunctionality, the capacity to form chemical bonds to at least two other monomer molecules.

Polymer:  A polymer is a large molecule made up of chains or rings of linked repeating subunits, which are called monomers. Man made  polymer is called plastic.

Polymerization:  Polymerization is a chemical reaction in which two or more molecules combine to form larger molecules that contain repeating structural units.

Plastics are mainly of two types:

1.  Thermoplastic: The plastic which melts on heating and reshaped and reused again is called thermoplastic. Polythene, polyvinyl chloride(PVC), polystyrene etc are examples of thermoplastic.

2. Thermosetting Plastic: A thermosetting plastic is a polymer that irreversibly becomes rigid when heated. Such a material is also known as a thermoset or thermosetting polymer. Initially, the polymer is a liquid or soft solid. Thermosetting plastics cannot be remolded and reused. Bakelite is an example of thermoplastic which is used to make heat and electric insulators.

Features of Plastics

Lightweight with a high strength-to-weight ratio

Can be manufactured inexpensively and mass produced

Water resistant

Shock resistant

Thermally and electrically insulating

 Uses of plastics

1. Making Plastic utensils and furniture

2. polythene bags

3.making heat and electric insulators

4. making artificial fiber to to make clothes