High Molecular Weight Poly(butyl methacrylate) by Reverse Atom Transfer Radical Polymerization in Miniemulsion Initiated by a Redox System

The reverse atom transfer radical polymerization of butyl methacrylate in miniemulsion, initiated with the redox pair hydrogen peroxide/ascorbic acid and mediated with copper(II) bromide tris[2-di(2-ethylhexyl acrylate)aminoethyl]amine, produced high molecular weight poly(butyl methacrylate) (Mn = 989 900, PDI = 1.25). The miniemulsion was carried out with 15% solids (based on 100% conversion), 10 wt % of the nonionic surfactant Brij 98 (based on monomer), and 3.8 wt % hexadecane (based on monomer), with the final weight-average particle diameter less than 110 nm. The use of the redox pair to initiate the polymerization also facilitated a relatively fast rate of polymerization. The polymerizations were carried out at 60 °C and typically reached their maximum conversion (with degrees of polymerization up to 6900) of ∼80% in only 8 h. Additionally, the polymerization of methyl methacrylate produced well-defined high molecular weight polymers with a controlled degree of polymerization and narrow molecular weight distribution.