Binary Copolymerization with Catalytic Chain Transfer. A Method for Synthesizing Macromonomers Based on Monosubstituted Monomers

Abstract

With appropriate choice of conditions, copolymerization of monosubstituted monomers [CH2CHX: e.g., styrene, butyl acrylate (BA)] in the presence of small amounts of an α-methylvinyl monomer [CH2C(CH3)Y: e.g., α-methylstyrene (AMS), methyl methacrylate (MMA), methacrylonitrile (MAN)] and a cobaloxime as chain transfer catalyst provides a route to macromonomers that are composed largely of the monosubstituted monomer and yet have a chain end derived from the α-methylvinyl monomer (−CH2−C(CH2)Y). The various factors (temperature, concentrations, type of cobaloxime, types of monomer) that influence molecular weight and end group purity and the importance of the various side reactions that may complicate the process are described. Macromonomer purity is enhanced by increasing the concentration of the α-methylvinyl monomer and reducing the cobaloxime concentration. It also depends on the structure of the cobaloxime, increasing in the series where the ligands are derived from dimethyl glyoxime < diethyl glyoxi...