Living polymerization definition

All CRP methods rely on a dynamic equihbration between tiny amounts of propagating radicals and various types of dormant species. The essence of the process is a rapid reversible deactivation of growing radicals. Radicals always terminate and therefore CRP is never living in the pure sense of the living polymerization definition. Indeed, lUPAC recommends to avoid using term Uving for the radical polymerization and suggests to use the term controlled reversible deactivation radical polymerization . 

Anionic polymerization of PL with alkali metal counterions as growing species has, perhaps, a measurable transfer to monomer (Scheme 11, R=H) as it could be estimated from Mn of the resulting PPL being not higher than 10 g moP even at room temperature.Thus, the question arises whether this system fully conforms to the living polymerization definition vide infra). 

NdN/TIBA/DIBAH/EASC and (2) NdV/DIBAH/EASC are in compliance with requirement No. 4 Increase of molar mass on sequential monomer addition . These results provide definitive proof in favor of a living polymerization. 

This review covers mainly the scientific literature that has appeared in relevant journals until early 2001 concerning the metal-catalyzed (or atom-transfer) living radical polymerization. The word living employed here simply refers to polymerizations that provide control over the molecular weights, the molecular weight distributions, and the chain end reactivity as do other living polymerizations. Its definition and use criteria, along with the word controlled , are still under discussion and have recently been discussed elsewhere.39 Thus, the discussion on the difference between these words is not to be treated here. 

Other multifunctional initiators include star polymers prepared from initiators via living radical or other living polymerizations. In particular, all of the star polymers via metal-catalyzed living polymerization, by definition, carry a halogen initiating site at the end of each arm, and thus they are potentially all initiators. Thus, star-block copolymers with three polyisobutylene-Mock-PMMA arms and four poly-(THF) -A/oc/F polystyrene or poly(THF)-Woc/c-polysty-rene-Wock-PMMA were synthesized via combination of living cationic and copper-catalyzed living radical polymerizations.381,388 Anionically synthesized star polymers of e-caprolactone and ethylene oxide have... 

Despite the fact that initiation of ONDCA does not proceed stoichiometrically with this type of initiator, a living polymerization within the limits of the classical definitions (no chain termination, no chain transfer)[2, 3] may be performed. In case polymerizations were started with NBE, well defined block-copolymers with regard to block-size and molecular weight, one block consisting of poly(ONDCA) and another of poly-NBE, may be prepared. 

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