Synthesis of silicone-methacrylate copolymers by ATRP using a nickel-based supported catalyst

A nickel (II) bromide catalyst immobilized onto crosslinked diphenylphosphinopolystyrene (PS-PPh₃/NiBr₂) was used for the synthesis of silicone-methacrylate copolymers by atom transfer radical polymerization (ATRP) of various methacrylate monomers using ω-bromide silicone chains as macroinitiator. The polymerization proved to be very well-controlled when a sufficient amount of soluble ligand, i.e., triphenylphosphine (PPh₃), was added to the polymerization medium. Under these conditions, this technique efficiently led to the production of different copolymers with controlled compositions and molecular weights as well as narrow polydispersity indices (M̄_w/M̄_n < 1.5). The recovered copolymers proved to be almost free of catalyst residues. Indeed, inductively coupled plasma (ICP) analysis revealed a metal content lower than 100 ppm, representing only a few percent of the initial metal content in the polymerization medium.