Molecular dynamics of poly(ethylene glycol)s studied by optical Kerr effect and Brillouin spectroscopy

Brillouin study of photopolymerization process of two-monomer systems

The results of Brillouin scattering investigations of two-component system: 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane/polyethylene glycol methacrylate (bis-GMA/PEGMM) containing 0, 30, 50, 70, 85 and 100 mol% of PEGMM are presented. For the first time the Brillouin spectroscopy was used to monitor the progress of the polymerization process. The polymerization was initiated by ultraviolet radiation (λ=365 nm), at temperature 20°C and 40°C. Some of the physical parameters characteristic for this system such as velocity V, adiabatic compressibility β(ad) and attenuation coefficient α of the acoustic waves have been estimated from Brillouin spectra as a functions of the polymerization time. The obtained results have been discussed in terms of changes of the elastic properties of the two-component system occurring during polymerization process and their dependence on bis-GMA/PEGMM system composition.

Elastic properties of some selected two-monomer systems as studied by Brillouin spectroscopy

We present results obtained by Brillouin scattering method for four two-component systems comprising of a high viscosity monomer and a low viscosity monomer. The monomers used were crosslinking (divinyl) or linear (monovinyl) ones. The investigated systems were: divinyl/divinyl-bis-GMA/TEGDM; divinyl/monovinyl-bis-GMA/PEGMM; monovinyl/divinyl-bis-MGMA/TEGDM and monovinyl/monovinyl-bis-MGMA/PEGMM; they were formulated at various molar ratios. The measurements have been performed in temperature range 293-353 K. The following physical parameters characterizing the investigated systems were estimated: hypersonic velocity V, attenuation coefficient α and adiabatic compressibility β, all as a function of temperature and monomer molar ratio. The obtained results have been discussed in terms of the influence of the system composition and viscosity on their elastic properties. Speed of changes of the adiabatic compressibility β as derivative have been also discussed in terms of both, the temperature as well as the component of molar ratio.