Classification of Polymers

Polymer : The term polymer refers to very large molecules having high molecular mass (10³ - 10⁷ μ). These are also referred to as macro molecules, which are formed by joining of repeating structural units on a large scale.

Polymers :

Source of availability :
Natural polymers :
Found in plants, animals.
eg : protein, cellulose, starch, resin, rubber.
Cellulose derivatives :
Cellulose acetate (Rayon), Cellulose nitrate, semi synthetic polymers.
Polythene :Nylon 6,6 , Buna -s, Synthetic polymers.

Structure of polymers :
Linear :
Consists of long straight chains.
eg : HDPE, PVC

Branched chain :
Contain linear chains having some branches
eg : LDPE

Cross linked (or) Network :
Contain strong covalent bonds between various linear polymer chains.
eg: Bakelite, Melamine.

Molecular forces :

Elastomer :
Weak inter molecular forces can be stretched.
eg : Buna - S, Buna - N, Neoprene.
Fibre : Thread forming solids which possess high tensile strength and modulus. Have hydrogen bonding crystalline nature.
eg : Nylon 6,6, Polyester.
Thermoplastic :
Linear of slightly branched bond chain molecules capable of repeatably softening and hardening forces between elastomers, fibres.
eg : Polythene, polystyrene, polyvinyl.
Thermosetting :
Cross linked or heavily branched molecules which on heating undergo extensive cross linking in moulds and become influenced can not be reused.
eg : Bakelite, urea formaldehyde resins etc.