Poly (tert-butyl)acrylate-b-isobutylene-b-styrene) terpolymer from a carbocationic initiator containing a latent radical initiating site

摘要

A poly(isobutylene-b-styrene) (PIB-PS) copolymer was synthesized via quasi-living carbocationic polymerization from an initiator containing a latent site for atom transfer radical polymerization (ATRP) initiation.The initiator,3,3,5-trimethyl-5-chlorohexyl acetate (TMCHA),was synthesized in four steps from methyl 3,3-dimethyl-4-pentenoate.The PIB block was created at - 70 deg C in a methylcyclohexane/methyl chloride (60:40) cosolvent system,using TiCl_4 as the catalyst,followed by sequential addition of styrene.The acetate head group of the resulting block copolymer was converted to a hydroxyl group using a strong base and subsequently esterified with 2-bromopropionyl bromide to create an initiating site for ATRP of tert-butyl acrylate,which was carried out using a Cu(I)Br/1,1,4,7,7,-pentamethyl-diethylenetriamine (PMDETA) catalyst system.The final terpolymers had compositions that were very close to theoretical.