New strategy for the synthesis of halogen-free acrylate macromonomers by atom transfer radical polymerization

Atom transfer radical polymerization (ATRP) of n-butyl acrylate and tert-butyl acrylate using 2-hydroxyethyl 2-bromoisobutyrate as a functionalized initiator and an excess of N,N,N 'N 'N " -pentamethyldiethylenetriamine (PMDETA) relative to the initiator and CuBr catalyst yields halogen-free polymers with a terminal hydroxyl function in a one-pot reaction. The Br atoms of the other terminus would be detrimental for the synthesis of graft copolymers via ATRP. In our approach they are replaced by hydrogen atoms via transfer from PMDETA at the end of the polymerization. The subsequent esterification of the hydroxyl group with methacryloyl chloride leads to well-defined macromonomers with predictable molecular weights and low polydispersities (M-w/M-n less than or equal to 1.2).