Polymerization is the method of combining many small molecules to create a single macromolecule. Monomers are small molecules that serve as the building blocks of polymers. Polymerization is classified into two categories based on the types of reactions involved: addition polymerization and condensation polymerization.
The main difference between addition and condensation polymerization is that in addition polymerization the polymers are formed by the addition of monomers 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.
The formation of addition polymers occurs by the repeated addition of monomer molecules which possess triple or double bonds.
The formation of ((C3H6)n) polypropene from (C3H6) propene, and ((C2H4)n) polythene from (C2H4) ethene.
- Homopolymers – The formation of addition polymers due to the polymerization of single polymeric species is called a homopolymers. For example, polythene (C2H4)n).
- Copolymers – The formation of addition polymers which occur due to by addition polymerization from two different monomers is called a copolymer. For example, Buna-N, Buna-S, etc.
The formation of condensation polymers occurs by the repeated condensation reaction between two different tri-functional or bi-functional monomeric units. In this type of reaction, small molecules such as alcohol, water, hydrogen chloride, etc. are eliminated.
are nylon 6, nylon 6, 6, terylene (dacron), etc. Formation of nylon 6, 6 occurs due to the condensation of (C6H16N2) hexamethylene diamine with (C6H10O4) adipic acid.