Addition polymers are formed by the repeated addition of monomers. No by-products are formed in this linkage.
Polyethene which is used for making plastic carry bags and toys are formed by the process of addition. The monomers either contain a double bond or have a ring structure containing three to seven atoms.
On the other hand, condensation polymers are formed when monomers condense while bonding. By-products are formed in this reaction and small molecules like water are lost. Most of the natural polymers are synthesized using this process.
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