Allyl Halide (Macro)initiators in ATRP: Synthesis of Block Copolymers with Polyisobutylene Segments

Abstract

Allyl halides (allyl-X) and polyisobutylene with allyl halide end group (PIB-allyl-X where X = Cl, Br) were investigated as (macro)initiators in atom transfer radical polymerization (ATRP). Studies with low molecular weight allyl halide initiators that model the PIB-allyl-X macroinitiator were performed first. Polymerization of styrene (St) using allyl halides in the presence of CuX/4,4′-di(5-nonyl)-2,2′-bipyridine (dNbpy) catalyst was controlled, but polystyrene with lower polydispersity was obtained with the Br-based initiator−catalyst system. ATRP of methyl methacrylate (MMA) initiated by allyl halides was not as successful. Polymerization of MMA with allyl-Cl and CuCl/dNbpy catalyst resulted in polymer with molecular weight 4 times higher than the predicted value. The polymerization initiated by allyl-Br in the presence of CuCl/dNbpy catalyst was better controlled but still resulted in polymers with molecular weights 2 times higher than the theoretical values. The addition of 10 mol % St to MMA signif...