Condensation polymerisation: In this type polymerisation, two or more bifunctional molecules undergo a series of independent condensation reactions with the elimination of simple molecules such as water, alcohol, hydrogen chloride, etc. to form a macromolecule.
For Example: nylon-6, 6, is formed by adipic acid and hexamethylenediamine.
Addition Polymerisation: In this type of polymerisation, the polymers are formed by the repeated addition of monomer molecules possessing double or triple bonds. For example, formation of polythene from ethane.