Controlled-"living" atom transfer radical polymerization of styrene in thesynthesis of amphiphilic diblock copolymers from a poly(ethyleneglycol) macroinitiator

Atom transfer radical polymerization (ATRP) of styrene was initiated by a p oly(ethylene glycol) macroinitiator prepared by quantitative esterification of MPEG2000 with 2-chloropropionyl chloride. The polymerization carried ou t at 130 degrees C catalyzed by addition of cuprous chloride and 2,2'-bipyr idine has been found to comply to the criteria for a "living" polymerizatio n, since a linear M-n versus monomer conversion plot was found in accordanc e with the theoretical line indicating essentially 100% initiating efficien cy. Also the polymerization is first order with respect to monomer concentr ation determined in two independent ways. The polydispersity index remained around 1.3 throughout the polymerization and no formation of homopolystyre ne could be detected.