Well-Defined Graft Copolymers of Methacrylate, Acrylate, and Styrene via Ruthenium-Catalyzed Living Radical Polymerization

The ruthenium-catalyzed living radical polymerization was first applied to the synthesis of a series of well-defined graft polymers with the controlled lengths of both the backbone and graft chains. The synthetic method was based on the ruthenium-catalyzed “grafting-from” polymerization of various monomers, such as methacrylate, acrylate, and styrene, from the backbone polymers also obtained via the ruthenium-catalyzed living radical polymerization. The backbone polymer was first synthesized by the ruthenium-catalyzed living radical random copolymerization of methyl methacrylate (MMA) and 2-(trimethylsilyloxy)ethyl methacrylate (TMSHEMA) followed by the in situ transformation of the silyloxyl group into the ester with a C–Br bond via direct reaction with the acid bromide (2-bromoisobutyryl bromide). The obtained multifunctional macroinitiator was employed for the ruthenium-catalyzed “grafting-from” radical polymerization of MMA, n-butyl acrylate, styrene, and TMSHEMA to afford a series of the graft polymers (Mw/Mn∼1.1) with controlled lengths of the backbone and graft chains.