▁the ▁only ▁used ▁catal yst , ▁it ▁is ▁a ▁medi ator . ▁ ▁For ▁this ▁reason ▁this ▁type ▁of ▁reaction ▁is ▁referred ▁to ▁as ▁c ob alt ▁medi ated ▁radical ▁polym er ization . ▁ ▁Introduction ▁About ▁half ▁of ▁all ▁commercial ▁polym ers ▁are ▁produced ▁by ▁radical ▁polym er ization . ▁Rad ical ▁polym er ization ▁( R P ) ▁re actions ▁have ▁several ▁advantage ous ▁properties : ▁ ▁A ▁wide ▁variety ▁of ▁mon om ers ▁can ▁be ▁polym er ized . ▁R P ▁re actions ▁are ▁toler ant ▁to ▁various ▁functional ▁groups . ▁R P ▁re actions ▁allow ▁a ▁large ▁temperature ▁range ▁of ▁operation ▁( – 1 0 0 ▁to ▁> 2 0 0   ° C ). ▁R P ▁re actions ▁are ▁generally ▁compatibility ▁with ▁several ▁re actions ▁conditions ▁( bul k , ▁solution , ▁( min i ) em ulsion ▁and ▁susp ension ). ▁R P ▁re actions ▁allow ▁a ▁relatively ▁simple ▁re actor ▁set - up , ▁and ▁are ▁hence ▁costs ▁effective . ▁ ▁However , ▁conventional ▁( free ) ▁R P ▁re actions ▁suffer ▁from ▁a ▁lack ▁of ▁control ▁over ▁the ▁polym er ▁mole cular - we ights ▁and ▁weight ▁distributions . ▁A ▁relatively ▁narrow ▁mole cular ▁weight - distribution ▁( M w / M n ) ▁is ▁usually ▁des irable , ▁as ▁broad ▁distribution ▁neg atively ▁influence ▁the ▁polym er ▁properties ▁of ▁( gener ally ▁at actic ) ▁polym ers ▁produced ▁by ▁R P . ▁Common ▁R P ▁also ▁does ▁not ▁allow ▁the ▁formation ▁of ▁block ▁cop