NCERT Solutions
Class 12 Chemistry
Polymers

Q.8
How can you differentiate between addition and condensation polymerisation?
Addition Polymer:-
The addition polymers are formed by the repeated addition of monomer
molecules possessing double or triple bonds, e.g., the formation of polythene
from ethene and polypropene from propene. However, the addition polymers
formed by the polymerisation of a single monomeric species are known as
homopolymers, e.g., polythene.
nCH2=CH2 à - (CH2-CH2)-n Homopolymer
Ethene Polythene
Condensation Polymer:-
The condensation polymers are formed by repeated condensation reaction
between two different bi-functional or tri-functional monomeric units. In these
polymerisation reactions, the elimination of small molecules such as water,
alcohol, hydrogen chloride, etc. take place. The examples are terylene (dacron),nylon 6, 6, nylon 6, etc. For example, nylon 6, 6 is formed by the condensation of hexamethylene diamine with adipic acid.
nH2N (CH2)6NH2 + nHOOC (CH2)4COOH à [NH (CH2)6NHCO (CH2)4CO]-n + H2O
Nylon (6, 6)