The process of combining a large number of small molecules to form a single macromolecule is known as polymerisation. The small molecules that act as the building blocks of polymers are called monomers. Based on the kinds of reactions involved, polymerisation is divided into two groups known as addition polymerisation and condensation polymerisation. Addition polymerisation is the process of repeated addition of monomers that possess double or triple bonds to form polymers. Condensation polymerisation is a process that involves repeated condensation reactions between two different bi-functional or tri-functional monomers. Given below, in a tabular column, is the difference between addition and condensation polymerisation.
| Addition Polymerisation | Condensation Polymerisation |
| Monomers must have either a double bond or triple bond. | Monomers must have two similar or different functional groups. |
| It results in no by-products. | It results in by-products such as ammonia, water and HCl. |
| The addition of monomers results in the formation of the polymer. | The condensation reaction between monomers results in the formation of the polymer. |
| The molecular weight of the resultant polymers is a multiple of the monomer’s molecular weight. | The molecular weight of the resultant polymer is not a multiple of the monomer’s molecular weight. |
| Lewis acids or bases, radical initiators are catalysts, in addition, polymerisation | Different molecules are used as catalysts in the process of condensation polymerisation. |
| Common examples of addition polymerisation are PVC, polyethene, Teflon etc. | Common examples of condensation polymerisation are nylon, bakelite, silicon, etc. |
The main difference between addition and condensation polymerisation is that in addition polymerisation the polymers are formed by the addition of monomer with no by-products whereas in condensation polymerization, the polymers are formed due to the condensation of more than one different monomers resulting in the formation of small molecules such as HCl, water, ammonia, etc., as by-products. Learn about other similar topics like the difference between Enantiomers and Diastereomers by registering with BYJU’S.
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