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

On the basis of phase separation temperatures (T-s) for poly(methyl methacr ylate)/poly(styrene-co-acrylonitrile) blends of different compositions, mea sured by small angle laser light scattering, we have studied dynamic theolo gical behavior of these blends at different temperatures below, near and ab ove T-s. The results showed that the time-temperature superposition princip le could be applied and the linear viscoelastic response emerged in the ter minal region at temperatures below T-g. However, it was found that the brea kdown of time-temperature superposition principle appeared, and viscoelasti c response deviated from the linear behavior in the terminal region at temp eratures near and above T-g. (C) 2001 Elsevier Science Ltd. All rights rese rved.