Answer:
Addition polymerization is a polymerization process that produces addition polymers. Addition polymers is a polymer that is formed by connecting or addition of the monomer units by a carbon-carbon bond without the use of other chemicals or without co-generation of other products.
It is different then condensation polymerization that co-generates other products or used other reactant chemicals. Polyyethene and polypropene are the examples of addition polymers.