Relationship between dynamic rheological behavior and phase separation of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends

On the basis of phase separation temperatures (Ts) for poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends of different compositions, measured by small angle laser light scattering, we have studied dynamic rheological behavior of these blends at different temperatures below, near and above Ts. The results showed that the time–temperature superposition principle could be applied and the linear viscoelastic response emerged in the terminal region at temperatures below Ts. However, it was found that the breakdown of time–temperature superposition principle appeared, and viscoelastic response deviated from the linear behavior in the terminal region at temperatures near and above Ts.