Single component dynamics in miscible poly(vinyl methyl ether)/polystyrene blends under hydrostatic pressure

By means of dielectric spectroscopy, we have studied the relaxation dynamics of poly(vinyl methyl ether) (PVME) in miscible blends with polystyrene (PS) at several concentrations in a broad range of pressure and temperature. Several interesting phenomena which take place in these kinds of blends have been investigated. In particular, the validity of the temperature-pressure superposition for a single component in a polymer blend over the whole composition range has been tested. We have also found that isobaric fragility for PVME in the blends increases with pressure whereas it does not change for pure PVME or even decreases for PS. Additionally, the confinement effects on PVME induced by the other component have also been analyzed. Finally, we discuss the ability of the density scaling to account for the low T-g component dynamics in the blend over a broad pressure-temperature range.