Question

Explain the following terms:
(a) Homopolymers
(b) Elastomers

Answer 1

Hint:Polymers are very high molecular mass substances in which each molecule consists of a very large number of simple repeating units joined together through covalent bonds in a regular fashion. The simple and reactive molecules from which the repeating structural units are derived are called monomers and the process by which these simple molecules are converted into Polymers is called polymerization.

Complete step by step answer:
(a) Homopolymers - The Polymers in which the repeating structural units are derived from only one type of monomer units are called homopolymers , for example polythene Is a polymer which is obtained by polymerization of ethene molecules .
Example of Homopolymer
\[{C_6}{H_5} - {\left( {C{H_2} - C{H_2}} \right)_n} - C{H_2} - C{H_2} + {C_6}{H_5} - {\left( {C{H_2} - C{H_2}} \right)_n} - C{H_2} - C{H_2}\]
$ \to {C_6}{H_5} - {\left( {C{H_2} - C{H_2}} \right)_n} - C{H_2} - C{H_2} - C{H_2} - \left( {C{H_2} - C{H_2}} \right) - {C_6}{H_5}\;(Polythene)$
(b) Elastomer - The Polymers in which the intermolecular forces of attraction between the polymer chains are the weakest are called elastomers. They are polymers which have a high degree of elasticity which means they have the ability to stretch out over 10 times their normal length and return to their original position when the force is withdrawn .
They consist of randomly coiled molecular Chains of irregular shape having a few cross links .
For example- Natural Rubber, Neoprene Rubber, Buna-s and Buna-N.
$n\;C{H_2} = CH - CH = C{H_2}\left( {{\text{1, 3 - Butadiene}}} \right) + n\,{C_6}{H_5}CH = C{H_2}\left( {{\text{Styrene}}} \right)$
$ - {\left( {C{H_2} - CH = CH - C{H_2} - CH - {C_6}{H_5} - C{H_2}} \right)_N}\left( {{\text{Butadiene - Styrene Polymer}}} \right)\left( {{\text{Buna - S}}} \right)$
Additional Information:
Polymer properties are closely related to their molecular mass, size and structure. The growth of the polymer chain during their synthesis is dependent upon the availability of monomers in the reaction mixture.

Note:Biodegradable polymers, a large number of polymers are quite resistant to the environmental degrading process and are thus responsible for the accumulation of polymeric solid waste materials. These solid wastes cause acute environmental problems and remain under graded for quite a long time.