condensation polymerization : releasing water as by product, occurs in monomer that has functional group that can react with each other e.g alcohol&carboxlic acid to form polyesters, carboxylic acid and amines to form polyamides,etc.
Radical Polymerization: occurs by propagating radical monomers or monomer that has unsaturated bonds, such as ethene, initiated by formation of radical from the monomer by using uv lights/other initiator, does not produce any by products