State and explain the terms :
Addition polymerisation

Explanation

Addition polymerisation. The process in which the polymer, is formed by the repeated addition of monomer molecules possessing double or triple bonds is called addition polymerisation.
For example, formation of polythene from ethene.
`underset("Ethene") (nCH_2= CH_2) overset("Polymerisation")to underset("Polyethene (a homopolymer)")([--CH_2 - CH_2 --]_n)`
Formation of Buna-S by the copolymerisation of butadiene and styrene is also addition polymerisation.
`underset("Butadiene")(nCH_2 = CH- CH = CH_2) +underset("Styrene")(n overset(C_6H_5)overset(|)CH= CH_2)`