Condensation polymerization and addition polymerization are two distinct methods for synthesizing polymers, which are large molecules composed of repeating subunits.

In condensation polymerization, two monomers react to form a polymer while also releasing a small molecule, typically water. This process is termed ‘condensation’ polymerization because it resembles the physical process of condensation, where water is produced. Importantly, the participating monomers in condensation polymerization must possess two functional groups to facilitate their reaction with one another.

Conversely, addition polymerization involves the direct joining of monomers without the release of any additional molecules. In this process, the monomers each contain a single functional group, enabling them to link together in a chain-like manner to form the polymer. This process is referred to as ‘addition’ polymerization since the monomers are simply added together without the generation of byproducts.

The choice of polymerization technique significantly influences the properties of the resulting polymer. For instance, condensation polymers, such as nylon and polyester, are commonly utilized in textiles due to their strength and durability. In contrast, addition polymers like polyethylene and polystyrene are frequently employed in packaging applications because of their lightweight nature and ease of molding into various shapes.

In summary, the primary distinction between condensation polymerization and addition polymerization lies in the elimination of a small molecule during the former process and the types of monomers involved. This difference leads to the formation of various types of polymers, each exhibiting unique properties.