One-pot synthesis for gradient copolymersviaconcurrent tandem living radical polymerization: mild and selective transesterification of methyl acrylate through Al(acac)3with common alcohols

Abstract

A series of gradient copolymers were synthesized by the ruthenium-catalyzed living radical polymerization (LRP) of methyl acrylate (MA) and aliphatic alcohols using aluminum acetylacetonate Al(acac)3. In this polymerization system, Al(acac)3was successfully used not only as an additive for the Ru-catalyzed LRP but also as a catalyst for the selective transesterification of an unsaturated ester monomer in mild conditions in a process known as concurrent tandem living radical polymerization. The resulting MA-based gradient copolymers showed well-controlled molecular weight and distribution in a one-pot reaction and exhibited a well-controlled gradient sequence in their polymer chain. Control of transesterification and the metal-catalyzed living radical polymerization (Mt-LRP) rate varied depending on the concentration of the Al(acac)3and the structure of varying alcohols, which were confirmed by1H NMR, SEC, and DSC analysis. In particular, this research opens a new synthetic methodology for preparing acrylate-based gradient copolymersviaconcurrent tandem LRP not limited to the synthesis of methyl methacrylate types of gradient copolymers.