An Investigation of Free-Radical Copolymerization Propagation Kinetics of Styrene and 2-Hydroxyethyl Methacrylate

Free-radical copolymerization propagation kinetics of styrene (ST) and 2- hydroxyethyl methacrylate (HEMA) have been investigated using pulsed laser polymerization (PLP) combined with size exclusion chromatography (SEC) and proton NMR. Monomer reactivity ratios for bulk ST/HEMA copolymerization are r HEMA = 0.49 and r ST = 0.27, with no significant variation with temperature found between 50 and 120 °C. The composition-averaged copolymerization propagation rate coefficient, k p,cop, is well represented by the implicit penultimate unit effect (IPUE) model. The copolymerization kinetics of HEMA with ST is quite similar to that of glycidyl methacrylate (GMA) with ST. A computational study based on quantum chemistry supports the finding that GMA and HEMA are more reactive toward ST radicals compared to alkyl methacrylates.