Brillouin spectroscopy studies of two-component polymerizable liquid system: 2,2-Bis[4-(2-hydroxymethacryloxypropoxy)phenyl]propane/benzyl methacrylate

Brillouin spectroscopy was used to investigate viscoelastic properties of a two-component system consisting of a high viscosity liquid (HVL) and a low viscosity liquid (LVL), both able to polymerize. The model liquids were: 2,2-bis[4-(2-hydroxymethacryloxypropoxy)phenyl]propane (abbreviated as bis-GMA, HVL) and benzyl methacrylate (BzMA, LVL). The viscosity of the system was regulated by changing the monomer ratio. Hypersonic velocity and attenuation coefficient were investigated in a temperature range covering viscoelastic relaxation process. The dependence of the longitudinal viscosity on the system composition was determined. Additionally, the Brillouin studies were accompanied by some supplementary experimental methods, like low frequency shear viscosity measurements and observations of phase transitions by differential scanning calorimetry (DSC). The investigated monomer mixtures were then polymerized in a light-induced process and the polymerization kinetic curves were measured to find the possible correlation between the viscoelastic properties of the monomer mixture (as observed by Brillouin spectroscopy) and the polymerization course.