Phase behaviour and borderline miscibility in blends of syndiotactic polystyrene with poly(vinyl methyl ether)

The state of miscibility and possible molecular aggregation in blends of se micrystalline syndiotactic polystyrene (s-PS) with poly(vinyl methyl ether) (PVME) were investigated by using differential scanning calorimetry (DSC), optical microscopy (OM) and scanning electron microscopy (SEM). The result s are then directly compared to the classical amorphous PS/PVME blend prepa red using exactly the same solvent and procedures. Similar to the classical amorphous a-PS/PVME, the semicrystalline s-PS/PVME exhibit the same scales of various molecular aggregation depending on composition leading to a so- called borderline miscibility, which is thoroughly discussed using the resu lts of T-g-composition relationship and morphology evidence. The behavior o f s-PS/PVME agrees mostly with that of a-PS/PVME, indicating that tacticity or crystallinity in s-PS does not affect the phase behaviour of s-PS/PVME in the amorphous domain. (C) 1999 Elsevier Science Ltd. All rights reserved .