What are polymers and how are they formed?

Polymers are large molecules made up of repeating subunits called monomers, formed through a process called polymerisation.

Polymers are essentially large molecules that are formed by joining together many smaller molecules, known as monomers. This process of joining monomers together to form a polymer is called polymerisation. The word 'polymer' comes from the Greek words 'poly' meaning many, and 'meros' meaning parts. Therefore, a polymer is essentially a 'many-part' molecule.

There are two main types of polymerisation: addition polymerisation and condensation polymerisation. In addition polymerisation, the monomers simply add together to form the polymer, with no other products. The monomers used in this process have a carbon-to-carbon double bond, which breaks open to allow the monomers to join together. This type of polymerisation is used to make polymers like polythene and PVC.

In condensation polymerisation, two different types of monomers join together to form the polymer, with a small molecule, usually water, being lost in the process. This type of polymerisation is used to make polymers like nylon and polyester.

Polymers have a wide range of properties and uses, depending on the type of monomers used and the conditions of polymerisation. For example, some polymers are very flexible and are used to make things like plastic bags, while others are very strong and are used to make things like car parts. The properties of polymers can also be modified by adding other substances, known as additives, during the polymerisation process. These can make the polymer more flexible, more resistant to UV light, or change its colour.

In summary, polymers are large, versatile molecules that are formed by joining together many smaller molecules, in a process called polymerisation. They have a wide range of uses in our everyday lives.