An Investigation of Free Radical Copolymerization Kinetics of the Bio-renewable Monomer γ-Methyl-α-methylene-γ-butyrolactone with Methyl methacrylate and Styrene
Résumé
The free-radical copolymerization propagation kinetics of the bio-renewable monomer γ-methyl-α-methylene-γ-butyrolactone (MeMBL) with styrene (ST) and with methyl methacrylate (MMA) have been investigated by the pulsed laser polymerization (PLP)—size exclusion chromatography (SEC) technique, in addition to DSC and proton NMR measurements. Monomer reactivity ratios for bulk MeMBL/ST and MeMBL/MMA copolymerizations are rMeMBL = 0.80 ± 0.04 and rST = 0.34 ± 0.04 and rMeMBL = 3.0 ± 0.3 and rMMA = 0.33 ± 0.01, respectively, with no significant variation with temperature found between 22 and 90 °C. The implicit penultimate unit effect (IPUE) model best represents the composition-averaged copolymerization propagation rate coefficient, kp,cop for the MeMBL/ST system. Arrhenius parameters were estimated for MeMBL homopolymerization and found to be quite similar to those of MMA. DSC results show that copolymers of well controlled composition can be produced to suit specific Tg requirements over a much higher temperature range than possible with current acrylic glasses