Synthesis of poly(methyl methacrylate)-b-polyethylene (PMMA-b-PE) block copolymers via conventional emulsion polymerization

Poly(methyl methacrylate)-b-polyethylene (PMMA-b-PE) block copolymers were recently obtained simply by involving omega-unsaturated PMMA oligomers prepared by CCTP in the radical polymerization of ethylene performed in dimethylcarbonate (DMC) solution (F. Baffie, G. Patias, A. Shegiwal, F. Brunel, V. Monteil, L. Verrieux, L. Perrin, D. M. Haddleton and F. D'Agosto, Angew. Chem., Int. Ed., 2021, 60, 25356-25364). However, omega-unsaturated PMMA oligomers are more effectively obtained as a latex by emulsion CCTP. In the present paper, these resulting latexes were used as seeds in the radical emulsion polymerization of ethylene in water. The effects of the methacrylic oligomer molar mass and the initial solids content of the seeds were investigated. Cryo-TEM analysis enabled demonstration of the formation of stable latexes composed of faceted spherical particles. The increase of molar mass correlated to the consumption of unsaturated oligomers with the polymerization time indicated the formation of block copolymers. The present study successfully transposed the chemistry performed in DMC solution and PMMA-b-PE block copolymers were obtained by a simple post-treatment of a PMMA latex.