Mechanical properties of amorphous PEI, PES, and PVC up to 11 GPa studied by Brillouin light scattering

We applied high-pressure Brillouin light spectroscopy to study the mechanical properties of representative amorphous polymers: polyetherimide (PEI), polyethersulfone (PES), and unplasticized polyvinylchloride (PVC). The pressure dependence of optical and elastic properties such as refractive indices and acoustic phonon velocities was obtained by employing both a forward, symmetric scattering and a backscattering geometry up to ~11 GPa. While PEI and PES showed longitudinal and transverse acoustic phonon modes simultaneously at above a certain pressure, PVC showed only one longitudinal acoustic phonon mode, which limited the access to further information. For PEI, PES, and PVC films, we successfully calculated pressure-dependent Poisson's ratios, bulk moduli, shear moduli, Young's moduli, and density-pressure isotherms. Furthermore, by using the Lorentz-Lorenz equation, we corroborated the conventional assumption that the mean polarizability of polymeric materials is nearly constant even when pressure is applied. •We measured the various optical, elastic, and mechanical properties of polyetherimide, polyethersulfone, and polyvinylchloride polymer up to ~11 GPa using Brillouin light scattering.•We measured the equation of state (EOS) for the polymer without transverse acoustic mode using Brillouin light scattering.•We corroborated the conventional assumption that the mean polarizability of polymeric materials is nearly constant using the Lorentz-Lorenz equation when pressure is applied.•We detected the coupling between the relaxation process and the LA phonon mode for polyetherimide and polyethersulfone using the FWHM analysis.•We obtained the experimental data for the development of EOS model of polymers.