Expanding the monomer scope of linear and branched vinyl polymerisations via copper-catalysed reversible-deactivation radical polymerisation of hydrophobic methacrylates using anhydrous alcohol solvents

Abstract

Cu-Catalysed reversible-deactivation radical polymerisation of hydrophobic methacrylate monomers in anhydrous alcohols has been expanded to explore the scope of this unusual choice of solvent. A range of linear methacrylic homopolymers with well-targeted molecular weight and low dispersity (Đ = 1.12–1.53) have been generated in anhydrous methanol and isopropanol with relative ease. These solvents are normally considered antisolvents and employed to precipitate such polymers; therefore, our studies have assessed the polymerisation reaction mixture homogeneity and extent of reaction control. Statistical copolymerisations with the bi-functional monomer, ethylene glycol di-methacrlylate (EGDMA), has led to branched statistical copolymers with weight average molecular weights up to M_w = 1.76 × 10⁶ g mol⁻¹; subsequent triple-detection size exclusion chromatography studies have provided insight into the impact of monomer structure on the extent of branching within the final isolated polymers. The ability to control branched copolymer molecular weights under these conditions through variation of EGDMA concentrations was seen to be highly dependent on methacrylate monomer chemistry. A number of factors which are likely to effect branching reactions during the polymerisation of hydrophobic methacrylates in anhydrous alcohols are discussed.