Pressure-dependent glass-transition temperatures of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends

The pressure-dependent glass-transition temperatures (T-g's) of poly(methyl methacrylate) (PMMA)/poly(styrene-co-acrylonitrile) (SAN) blends were determined by pressure-volume-temperature (PVT) dilatometry via an isobaric cooling procedure. The Gordon-Taylor and Fox equations were used to evaluate the relationships between the T-g's and compositions of the PMMA/SAN system at different pressures. The relationships were well fitted by the Gordon-Taylor equation, and the experimental data for T-g positively deviated from the values calculated with the Fox equation. Also, the influence of the cooling rate (during the PVT measurements) on T-g was examined.