Question

Explain the following terms giving a suitable example for each.
i.) Elastomers
ii.) Condensation polymers
iii.) Addition polymers

Answer 1

Hint: As the name suggests, elastomer means a material with an ‘elastic’ property. Similarly, condensation polymer is the type of polymer manufactured via ‘condensation’ process and addition polymer is the type of polymer manufactured via ‘addition’ of individual monomers. Complete step by step solution: Elastomers –
It is a type of polymer which has a unique property of ‘elasticity’. They are also very ‘viscous’ or dense in nature. The monomers in elastomers are bonded by weak intermolecular forces, as a result of which, they are viscoelastic in nature. They generally have a lower Young’s modulus and higher yield strength. Being elastic in nature, they regain their shape after being stretched.
For example – Natural rubber, polybutadiene, neoprene, etc.

Condensation polymers –
As the name suggests, condensation polymers are those which are prepared by the process of condensation, i.e. the process of joining two molecules by losing a small molecule, such as water or methanol.
It is also known as step-growth polymerization.
For example – PET (Polyethylene terephthalate) is made up of condensation of ethylene glycol and terephthalic acid by removal of a water molecule.

Addition polymers –
As the name suggests, addition polymers are those which are prepared by the process of addition of monomers via addition across the unsaturated bond (generally a double bond) to form a long polymeric chain.
Unlike in condensation polymerization, it does not include removal of any molecule.
For example, Polyvinyl chloride is made by an additional reaction between vinyl chloride monomers.

Additional Information: Young’s modulus is a mechanical property which measures the ‘stiffness’ of a solid material. It is expressed as a ratio between stress (force per unit area) and strain (proportional deformation) of a material.

Note: Elastomers are very widely used in motor vehicles – in its components like tyres and thermoset. They are also used in cable and wires; as adhesives and sealants in construction, etc. Condensation polymers such as PET are used in making food grade plastic bottles. Additional polymers like polystyrene are used in the manufacture of food-grade yoghurt cups.