Facile synthesis of gradient copolymers via semi-batch copper(0)-mediated living radical copolymerization at ambient temperature

摘要

In this work, we report an example of the facile synthesis of methyl methacrylate/tert-butyl acrylate (MMA/tBA) gradient copolymers (poly(MMA-grad-tBA) using the Cu(0) and conventional ATRP ligands as catalysts in DMF solvent at 25 degrees C. Semi-batch copper(0)-mediated living radical copolymerization technique (Cu(0)-mediated LRP) was used for achieving the chain gradient microstructure of the resulting copolymers. We also compared copolymerizations with two different ATRP ligands at ambient temperature allowing control over the molecular weight and polydispersity with a quarter of catalyst concentration versus a conventional ATRP in dipolar protic solvent (i.e. DMF), while the reaction temperature up to 80 degrees C in a non-polar medium (i.e. toluene) in order to reach the above polymerization efficiency. The addition of a small amount of reducing agent (i.e. hydrazine hydrate) into the reaction system allows the reaction proceeding in the oxygen tolerant system without losing control and decreasing total conversion such as using the reagents without deoxygenating.