How can you differentiate between addition and condensation polymerization?

In addition polymerization, the molecules of the same or different monomers add together to form a large polymer molecule. The monomers used are unsaturated compounds example alkenes, alkadienes and their derviatives. This mode of polymerisation leading to an increase in chain length. Some addition polymers are polythene, Teflon, PAN,etc.

Condensation polymerization is a process in which two or more bi-functional molecules undergo a series of condensation reactions with the elimination of some simple molecules as water, alcohol etc., and leading to the formation of high molecular mass polymers. For example terylene is example of condense polymer.