Scalable Routes to Acrylate and Methacrylate Block Copolymers via Copper-Mediated Reversible Deactivation Radical Polymerization

Abstract

Cu-mediated reversible deactivation radical polymerization (RDRP) is investigated as a method to produce (meth)acrylic polymers of high chain-end functionality and well-defined structure, enabling the production of uniform block copolymer materials. The use of inexpensive reagents with scale-appropriate reactor configurations is a key feature in overcoming the hurdles to commercialization. Using methyl acrylate (MA) as a model system, reaction conditions and feeding strategies were optimized in a semibatch system to reach >95% monomer conversion and 70 wt % polymer in solution in 1.5 h with excellent control (Đ = 1.10). It was concurrently demonstrated that prepolymerization in the copper tube reactor could be eliminated while still providing a chain-extendible species, a result that simplifies reactor operation, offers greater flexibility in initiator choice, and improves compositional control of the final product. The conditions developed for the homopolymerization system were applied to produce acrylate-acrylate and acrylate-methacrylate block copolymers, also exploring the influence of block order. Achieving high conversions for each monomer fed, reactions were completed in 4 h or less with no intermediate purification or additional catalyst, thus yielding a scalable method of producing block copolymer materials at Cu levels <100 ppm.