A dielectric study of secondary relaxations and the “memory effect” in two compatible polystyrene blends

Abstract Dielectric permittivities and loss tangents of 10 and 30% poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)–polystyrene (PS) blends and 10 and 25% poly(vinyl methyl ether) (PVME)–polystyrene blends have been measured from 80 to 360 K at 1 and 10 kHz. The PPO‐PS blends have two secondary relaxations below Tg and the PVME‐PS blends have three regions. All blends have a β process which appears near 290 K, is independent of PPO or PVME concentration, and is associated with the local modes of motions of PS chains. It is suggested that the β process of PS allows a dipolar reorientation of the PPO or PS chain segments by creating more favorable surroundings for the motions of the latter. The effect of physical aging in the PPO‐PS blend is substantial but the “memory effect” is significantly less. This is due to the lower contribution to tanδ from the β process of the blend.