Explain the classification of polymers based on their source and structure .

Explanation

On the basis of source polymers are classified into three types.
1) Natural polymers
2)Semi synthetic polymers
3) Synthetic polymers
1) Natural polymers : The polymers which are obtained from natural sources such as plants and animals are called natural polymers.
E.g : Starch ,cellulose ,rubber etc.
2) Semi synthetic polymers : The polymers which are synthetic derivatives of the natural polymers are called semisynthetic polymers.
E.g: cellulose rayon , cellelose ,nitrate.
3) Synthetic polymers : The polymers which are artificially prepared i.e .man -made are called synthetic polymers.
These have wide applications in daily life as well as in industry.
E.g : Plastic ,Nylon 6,6 synthetic rubbers .
Classification of polymers on the basis of structure:
i) Linear polymers : It is one in which the repeating units are similar to the links in a very long chain .

polythene ,PVC etc.
ii) Branched chain polymers : It is one i which some of the molecules are attached as side chains to the linear chains .

E.g : Low density polythene (LDPE) etc.
iii) Cross linked (or) network polymers : More branching at random points connecting many chains give rise to nerwork (or) cross linked polymers .

E.g : Bakelite ,melamine etc.