Nitroxide-mediated living radical polymerization of 2-hydroxyethyl acrylate and the synthesis of amphiphilic block copolymers

Nitroxide-mediated radical polymerizations of 2-hydroxyethyl acrylate (HEN) were performed in bulk, in organic solvent (N,N-dimethylformamide): and in aqueous media at, 100-120 degreesC, using an alkoxyamine initiator based on N-tert-butyl-N-(1-diethyl phosphono-2,2-dimethylpropyl) nitroxide, SG1. By the addition of free nitroxide (6-12 mol% with respect to the initiator), the polymerizations were controlled, exhibiting a linear relationship of ln([M](0)/[M]) vs time and M-n vs conversion up to 50-60% conversion. Poly(HEA) with M-n approximate to 90 000 and M-w/M-n < 1.3 can be obtained by bulk polymerization. Solution polymerizations of HEA in N,N-dimethylformamide and in water exhibit comparable kinetics to those of HEA bulk polymerizations at the same temperature. Chain transfer to polymer produced up to 1.7 mol%, branches for poly(HEA) depending on the reaction conditions. with a trend of increasing long chain branching with conversion. Amphiphilic block copolymers of poly(BA-b-HEA) with different molecular weights and block composition were synthesized from a poly(n-butyl acrylate) (pBA) macroinitiator.