Classification of polymers according to the mode of synthesis:
(1) Addition polymers
(2) Condensation polymers
(1) Addition polymers:
These are the products formed where the monomer units are repeatedly added to form long chain without the elimination of any bi-product molecules. Example: polyethylene, polypropylene, PVC, etc.
(2) Condensation polymers:
Condensation polymers are formed through a condensation reaction where molecules join together losing small molecules as bi-products such as waters, then the product is formed is called condensation polymer. Example: polyester, nylon 6.6, etc.