 Some other less common polymerization include radiation-induced polymerization, ring-opening olefin metathesis polymerization, polycondensation reactions, and iniferter-induced polymerization.The grafting to method involves the use of a backbone chain with functional groups A that are distributed randomly along the chain.The formation of the graft copolymer originates from the coupling reaction between the functional backbone and the end-groups of the branches that are reactive.