Nitroxide mediated suspension polymerization of methacrylic monomers

Suspension polymerization offers a scalable route to the synthesis of poly(methacrylic) resins with controlled molecular weight and complex macromolecular architectures, as is demonstrated herein, using 3-(((2-cyariopropan-2-yl)oxy)(cyclohexyl)amino)-2,2-dimethy1-3-phenylpropanenitrile for the first reported synthesis of methacrylic homopolymers by nitroxide mediated suspension polymerization. The limits of bulk polymerizations are overcome such that both methyl methacrylate (MMA) and n-butyl methacrylate (BMA) are successfully polymerized to high conversion with control over the molecular weight up to 100,000 g/mol and with a reasonably narrow molecular weight distribution. Partitioning of the nitroxide between the aqueous and organic phases leads to inhibition of polymerization in the aqueous phase and thus prevents the formation of small polymer particles by emulsion polymerization, allowing the aqueous phase to be recycled. Block copolymers can readily be made at solids content up to 40% by sequential monomer addition, offering the potential for scalable synthesis of controlled macro-molecular architectures by NMP in aqueous media. (C) 2017 Elsevier B.V. All rights reserved.