•`color{green}("Polymer ")` : The term polymer is defined as very large molecules having high molecular mass `(10^3-10^7u)`. These are also referred to as `color{green}("macromolecules")`, which are formed by joining of repeating structural units on a large scale.

•`color{green}("Monomer ")` : The repeating structural units are derived from some simple and reactive molecules known as monomers and are linked to each other by covalent bonds.

•`color{green}("Polymerisation ")` : The process of formation of polymers from respective monomers is called polymerisation. The transformation of ethene to polythene and interaction of hexamethylene diamine and adipic acid leading to the formation of Nylon 6, 6 are examples of two different types of polymerisation reactions.

• `color{green}("Natural Polymers ")` : These polymers are found in plants and animals. Examples are proteins, cellulose, starch, resins and rubber.

• `color{green}("Semi-synthetic Polymers ")` : Cellulose derivatives as cellulose acetate (rayon) and cellulose nitrate, etc. are the usual examples of this sub category.

• `color{green}("Synthetic Polymers ")` A variety of synthetic polymers as plastic (polythene), synthetic fibres (nylon 6, 6) and synthetic rubbers (Buna-S) are examples of man made polymers extensively used in daily life as well as in industry.

•`color{green}("Linear Polymers ")` : These polymers consist of long and straight chains. The examples are high density polythene, polyvinyl chloride, etc. These are represented as shown in fig.1.

•`color{green}("Branched Chain Polymers ")` : These polymers contain linear chains having some branches, e.g. low density polythene.

•`color{green}("Cross Linked or Network Polymers ")` : These are usually formed from bi-functional and tri-functional monomers and contain strong covalent bonds between various linear polymer chains, e.g. bakelite, melamine, etc.

• `color{green}("Addition Polymers ")`: The addition polymers are formed by the repeated addition of monomer molecules possessing double or triple bonds.

`color{green}("Homopolymer ")`: The addition polymers formed by the polymerisation of a single monomeric species are known as homopolymers, e.g., polythene.

•`color{green}("Copolymer ")` : The polymers made by addition polymerisation from two different monomers are termed as copolymers, e.g., Buna-S, Buna-N, etc.

• `color{green}("Condensation Polymers ")` : The condensation polymers are formed by repeated condensation reaction between two different bi-functional or tri-functional monomeric units.

`color{green}("Copolymerisation ")` : It is a polymerisation reaction in which a mixture of more than one monomeric species is allowed to polymerise and form a copolymer.