Block copolymers of styrene and p-acetoxystyrene with polyisobutylene by combination of living carbocationic and atom transfer radical polymerizations

Successful combination of quasiliving carbocationic (QLCP) and atom transfer radical polymerizations (ATRP) was carried out by initiating ATRP with polyisobutylene (PIB) macroinitiators obtained by QLCP. It has been found that 1-chloro-1-phenylethyl-telechelic PIBs with M̄_n of 7 800 and 30 700 are efficient macroinitiators for ATRP of styrene in bulk and in xylene solution and for p-acetoxystyrene (pAcOSt) in xylene. Size exclusion chromatography (SEC) traces clearly indicated quantitative initiation and the formation of the desired polystyrene-block-polyisobutylene-block-polystyrene (PSt-PIB-PSt) and PpAcOSt-PIB-PpAcOSt triblock copolymers. Experiments also revealed absence of thermal self-initiation of styrene under ATRP conditions.