Structural Control of Poly(Methyl Methacrylate)-g-poly(Lactic Acid) Graft Copolymers by Atom Transfer Radical Polymerization (ATRP)

Atom transfer radical copolymerization of methyl methacrylate (MMA) and (meth)acrylate-terminated poly(lactic acid) (PLA) macromonomers was investigated. The relative reactivity of methacrylate-terminated macromonomer (1/ r MMA = 1.75) and acrylate-terminated macromonomer (1/ r MMA = 0.61) was close to that of 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate, respectively. The difference in reactivity in ATRP and conventional radical polymerization is discussed in terms of the diffusion control effect. A mixture of methacrylate-terminated macromonomer and acrylate-terminated macromonomer was copolymerized with MMA by ATRP to give a homogeneously branched PMMA-g-PLA graft copolymer with low polydispersity ( M w / M n = 1.15).